Is Joshua Grubbs pulling the wool over our eyes with his "perceived porn addiction" research?

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UPDATE: A new study (Fernandez et al., 2017) tested and analyzed the CPUI-9, a purported "perceived pornography addiction" questionnaire developed by Joshua Grubbs, and found that it couldn't accurately assess "actual porn addiction" or "perceived porn addiction" (Do Cyber Pornography Use Inventory-9 Scores Reflect Actual Compulsivity in Internet Pornography Use? Exploring the Role of Abstinence Effort). It also found that 1/3 of the CPUI-9 questions should be omitted to return valid results related to “moral disapproval”, “religiosity”, and "hours of porn use." The findings raise significant doubts about conclusions drawn from any study that has employed the CPUI-9 or relied on studies that employed it. Many of the new study's concerns and criticisms mirror those outlined in the following critique.

UPDATE 2: Research Suggests the Grubbs, Perry, Wilt, Reid Review is Disingenuous ("Pornography Problems Due to Moral Incongruence: An Integrative Model with a Systematic Review and Meta-Analysis") 2018


A new concept has recently appeared in a rash of papers and articles: "perceived porn addiction." It was spawned by Joshua Grubbs and thoroughly examined in the YBOP analysis: Critique of "Perceived Addiction to Internet Pornography and Psychological Distress: Examining Relationships Concurrently and Over Time" (2015). Here are a few of the headlines birthed from that study:

  • Watching Porn Is OK. Believing In Porn Addiction Is Not
  • Perceived Addiction To Porn Is More Harmful Than Porn Use Itself
  • Believing You Have Porn Addiction Is the Cause of Your Porn Problem, Study Finds

Here we revisit Joshua Grubbs's work as he continues to publish "perceived porn addiction" papers. In this 2015 press release Grubbs suggests that pornography use itself doesn't cause any problems:

"It doesn't seem to be the pornography itself that is causing folks problems, it's how they feel about it,"

"Perceived addiction involves a negative interpretation of your own behavior, thinking about yourself, like, 'I have no power over this' or 'I'm an addict, and I can't control this.'

Grubbs sums up his views in this extraordinary 2016 Psychology Today article, claiming that porn addiction is nothing more than religious shame.

Being labeled "porn addict" by a partner, or even by oneself, has nothing to do with the amount of porn a man views, says Joshua Grubbs, assistant professor of psychology at Bowling Green University. Instead, it has everything to do with religiosity and moral attitudes toward sex. In short, he says, "It's shame-motivated."...

....Grubbs calls it "perceived pornography addiction." "It functions very differently from other addictions."

If Josuha Grubbs was accurately quoted, the above claims border on propaganda, as we will show that:

  1. Grubbs's questionnaire assesses only actual porn addiction, not "perceived porn addiction." That porn addiction doesn't "function differently from other addictions," and that Grubbs has not shown that it does. In fact, Grubbs based his questionnaire on (standard) drug addiction questionnaires.
  2. Contrary to his statement above, the amount of porn used is strongly related to scores on Grubbs's porn addiction questionnaire (CPUI). In fact, Grubbs's studies reveal that porn addiction (CPUI sections 2 & 3) is far more related to the amount of porn viewed than it is to religiosity.
  3. Moreover, "hours of use" are not a reliable measure of (proxy for) addiction. Previous studies have established that "hours of porn viewed" aren't linearly correlated with porn addiction scores or symptoms. Many additional variables of use also contribute to the development of a porn addiction.

Beyond these evident challenges to Grubbs's "porn addiction is only religious shame" claim, his model crumbles when we consider that:

  1. Religious shame doesn't induce brain changes that mirror those found in drug addicts. Yet there are some 39 neurological studies reporting addiction-related brain changes in compulsive porn users/sex addicts.
  2. The preponderance of studies report lower rates of compulsive sexual behavior and porn use in religious individuals (study 1, study 2, study 3, study 4, study 5, study 6, study 7, study 8, study 9, study 10, study 11, study 12, study 13, study 14, study 15, study 16, study 17, study 18, study 19, study 20, study 21, study 22, study 23, study 24)
  3. This means Grubbs's sample of religious porn users is inevitably skewed (see below). It also means that "religiosity" does not predict porn addiction.
  4. Many atheists and agnostics develop porn addiction. Two 2016 studies on men who had used porn in the last the last 6 months, or in the last 3 months, reported extraordinarily high rates of compulsive porn use (28% for both studies).
  5. "Perceived addiction" obviously couldn't induce chronic erectile dysfunction, low libido and anorgasmia in healthy young men. Yet numerous studies link porn use to sexual dysfunctions and lower sexual satisfaction, and ED rates have inexplicably skyrocketed by 1000% in men under 40 since "tube" porn arrived in porn users' lives.
  6. This 2016 study on treatment-seeking porn addicts found that religiosity did not correlate with negative symptoms or scores on a sex addiction questionnaire.
  7. This 2016 study on treatment-seeking hypersexuals found no relationship between religious commitment and self-reported levels of hypersexual behavior and related consequences.

In the following sections we will address Grubbs's major claims, look deeper into his data and methodology, and suggest alternative explanations for his claim that religiosity is related to porn addiction. But first let's start with the 3 pillars upon which Grubbs builds his assorted papers.

For Grubbs's claims to be valid ALL of these 3 must be true and supported by actual research:

1) The Grubbs Cyber Pornography Use Inventory (CPUI) must assess "perceived porn addiction" rather than actual porn addiction.

  • It does not. The CPUI assesses actual porn addiction, as Grubbs himself stated in his original 2010 paper validating the CPUI (more below). In fact, the CPUI was only validated as an actual porn addiction test, and never as a "perceived addiction" test. With no supporting scientific justification, in 2013, Grubbs unaccountably re-labeled his porn addiction test a "perceived porn addiction" test.
  • Note: In Grubbs’s studies he uses the phrase “perceived addiction” or “perceived porn addiction” to denote the total score on his CPUI test (an actual porn addiction test). This is lost in translation due to the frequent repetition of “perceived addiction,” instead of the accurate, spin-free label: “the Cyber Pornography Use Inventory score."

2) Grubbs must have found little to no correlation between hours of use and CPUI scores (porn addiction).

  • No again. For example, Grubbs et al. 2015 reveals a strong correlation between hours of use and CPUI scores. From p. 6 of the study:

"Additionally, average daily pornography use in hours was significantly and positively associated with depression, anxiety, and anger, as well as with perceived addiction [total CPUI score]."

  • Grubbs's second 2015 study reported a stronger correlation between CPUI scores and "hours of porn use" than it did between CPUI scores and religiosity.

How could Grubbs claim in Psychology Today that porn addiction "has nothing to do with the amount of porn a man views," when his studies reveal that quantity of use was "significantly and positively" correlated with CPUI scores?

3) Other studies must have reported that the amount porn used is linearly correlated with symptoms of porn addiction or scores on porn addiction tests.

  • They did not. Other research teams have found that the variable "hours of use" is not linearly correlated with cybersex addiction (or video-gaming addiction). That is, addiction is more reliably predicted by other variables than "hours of use" anyway, so the materiality of Grubbs's claims is questionable even if his methodology were sound and his claims were accurate. (Not the case.) "Hours of use" is not a reliable proxy for "porn addiction," so neither correlations with it nor lack of correlations with it can have the vast significance Grubbs presumes.

Most of the Grubbs-generated headlines and claims depend upon all 3 of the above points being true. They are not. We now examine these 3 pillars and the details surrounding Grubbs's studies and claims.

SECTION 1: The Myth of "Perceived" Porn Addiction:

The Cyber Pornography Use Inventory (CPUI): It's an actual addiction test.

Important to note:

  • Whenever Grubbs uses the phrase "perceived addiction" he really means the total score on his CPUI.
  • The CPUI is divided into 3 sections, which becomes very important later on as we examine how scores on each section correlate with other variables such as "hours of use" and "religiosity."
  • Each question is scored using a Likert scale of 1 to 7, with 1 being "not at all," and 7 being "extremely."


1. I believe I am addicted to Internet pornography.

2. I feel unable to stop my use of online pornography.

3. Even when I do not want to view pornography online, I feel drawn to it


4. At times, I try to arrange my schedule so that I will be able to be alone in order to view pornography.

5. I have refused to go out with friends or attend certain social functions to have the opportunity to view pornography.

6. I have put off important priorities to view pornography.


7. I feel ashamed after viewing pornography online.

8. I feel depressed after viewing pornography online.

9. I feel sick after viewing pornography online.

In reality, Grubbs's Cyber Pornography Use Inventory (CPUI) questionnaire is very similar to many other drug and behavioral addiction questionnaires. Like other addiction tests, the CPUI assesses behaviors and symptoms common to all addictions, such as: the inability to control use; compulsion to use, cravings to use, negative psychological, social and emotional effects; and preoccupation with using. In fact, only 1 of the 9 CPUI questions above even hints at "perceived addiction."

Yet we are told that a person's total score for all 9 questions is synonymous with "perceived addiction" rather than addiction itself. Very misleading, very clever, and without any scientific basis. Agnotology fodder, anyone? (Agnotology is the study of culturally induced ignorance or doubt, particularly the publication of inaccurate or misleading scientific data designed to confuse the public about the state of research in a particular field. Big Tobacco is credited with inventing the field of agnotology.)

Note that decades of established addiction assessment tests for both chemical and behavioral addictions rely on similar questions as the CPUI to assess actual, not merely perceived, addiction. CPUI questions 1-6 assess core addiction behaviors as outlined by the 4 Cs, while questions 7-9 evaluate negative emotional states after using porn. Let's compare the CPUI to a commonly used addiction assessment tool known as the "4 Cs." The CPUI questions that correlate with the four Cs are noted as well.

  • Compulsion to use (2, 3)
  • Inability to Control use (2, 3, maybe 4-6)
  • Cravings to use (3 especially, but 1-6 could be interpreted as cravings)
  • Continued use despite negative consequences (4-6, perhaps 7-9)

Addiction experts rely on assessment tools like the 4Cs as indicating addiction because neuroscientists have correlated the symptoms those questions with underlying addiction-related brain changes in decades of basic-research studies. See the public policy statement of the American Society of Addiction Medicine. In short, the Grubb's CPUI is an actual porn addiction test; it was never validated for "perceived addiction."

The initial 2010 Grubbs study said the CPUI assessed actual porn addiction

In Grubbs's initial 2010 paper he validated the Cyber-Pornography Use Inventory (CPUI) as a questionnaire assessing actual porn addiction. The phrases "perceived addiction" and "perceived porn addiction" do not appear in his 2010 paper. To the contrary, Grubbs et al., 2010 clearly states in several places that the CPUI assesses genuine porn addiction:

The previously described models proposed for understanding behavioral addictions were the primary theoretical assumptions used to derive the instrument for this study, the Cyber-Pornography Use Inventory (CPUI), patterned after the Internet Sex Screening Test developed by Delmonico (Delmonico & Griffin, 2008). The CPUI design was based on the principle that addictive behavior is characterized by an inability to stop the behavior, significant negative effects as a result of the behavior, and a generalized obsession with the behavior (Delmonico & Miller, 2003).

The CPUI does indeed show promise as an instrument assessing Internet pornography addiction. Whereas previous instruments, such as the ISST, had assessed only broad-spectrum online sexual addiction, this scale did demonstrate promise in specifically assessing Internet pornography addiction. Furthermore, the items on the previously explained Addictive Patterns scale seem to find some level of theoretical support and potential construct validity when compared with the diagnostic criteria for both Substance Dependence and Pathological Gambling, an ICD.

Finally, five of the items on the Addictive Patterns scale from the original Compulsivity scale seem to directly tap into the individual’s perceived or actual inability to stop the behavior in which they are engaging. Inability to stop a problematic behavior under any circumstances is not only an important diagnostic criterion for both SD and PG, but it can also can be thought of as one of the core elements of both addiction, as manifested in SD, and ICDs (Dixon et al., 2007; Potenza, 2006). It seems that it is this inability that creates the disorder.

In a 2013 study Grubbs reduced the number of CPUI questions from 32 (or 39 or 41) to the current 9, and re-labeled his actual, validated porn addiction test as a "perceived porn addiction" test (here's a 41-question version of the CPUI). He did so without any explanation or justification and proceeded to use the phrase "perceived addiction" 80 times in his 2013 paper. That said, Grubbs hinted at the true nature of the CPUI-9 in this excerpt from the 2013 paper:

"Last, we found that the CPUI-9 was strongly positively associated with general hypersexual tendencies, as measured by the Kalichman Sexual Compulsivity Scale. This points to the high degree of interrelatedness between compulsive pornography use and hypersexuality more generally."

Let's be very clear - the CPUI was never validated as an assessment test differentiating actual porn addiction from "perceived porn addiction." This means the public is relying only on Grubbs's word that his revised test can differentiate between "perceived porn addiction" and the "actual porn addiction" the CPUI was originally validated to assess. How scientific is it to re-label a validated test as something altogether different without validating the radically altered use of the test?

Why did Joshua Grubbs re-label the CPUI a "perceived" porn addiction test?

While Grubbs himself didn't claim his test could sort perceived from actual addiction, his employment of the misleading term ("perceived addiction") for scores on his CPUI-9 instrument have led others to assume his instrument has the magical property of being able to discriminate between "perceived" and "real" addiction. This has done enormous damage to the field of porn addiction assessment because others rely on his papers as evidence of something they do not, and cannot, deliver. No test exists that can distinguish "real" from "perceived" addiction. Merely labeling it as such cannot make it so.

How did this happen? It's not unusual for academic journal editors and reviewers to require substantial revisions before they accept a paper for publication. Joshua Grubbs said in an email that a reviewer of his second CPUI-9 study caused him and his co-authors of the 2013 study to alter the "porn addiction" terminology of the CPUI-9 (because the reviewer sneered at the "construct" of porn addiction). This is why Grubbs changed his description of the test to a "perceived pornography addiction" questionnaire. In essence an anonymous reviewer/editor at this single journal initiated the unsupported, misleading label of "perceived pornography addiction." The CPUI has never been validated as an assessment test differentiating actual porn addiction from "perceived porn addiction." Here's Grubbs tweeting about this process, including the reviewer's comments:

Josh Grubbs @JoshuaGrubbsPhD

On my 1st paper on compulsive porn use: "This construct [porn addiction] is as meaningful to measure as experiences of alien abduction: it's meaningless."

Nicole R Prause, PhD @NicoleRPrause 

You or reviewer?

Josh Grubbs @JoshuaGrubbsPhD

Reviewer said it to me

Josh Grubbs @JoshuaGrubbsPhD  Jul 14

Actually what led to my perceived addiction work, I thought about the comments as revised the focus.

There's no historical precedent for a "perceived addiction" assessment test

The two studies Grubbs consistently cites (1, 2) to imply that his concept of "perceived addiction" is established/legitimate were done on smokers, and neither supports the concept of "perceived addiction" as Grubbs uses it. First, neither study suggests, as Grubbs does with porn, that actual cigarette addiction doesn't exist. Nor did either of those studies claim to have developed a questionnaire that could distinguish or isolate "perceived addiction" from actual addiction. Both studies focused instead on assessing how future success in quitting smoking related to earlier self-reports of addiction.

There is no questionnaire for "perceived addiction" to anything - substance or behavior - including pornography use (regardless of Grubbs's claims). There's a good reason 'Google Scholar' returns zero results for the following "perceived addictions":

Other researchers predictably use the CPUI as an actual porn addiction test

Reality check: other researchers describe the CPUI as an actual porn addiction assessment questionnaire (as that's what it was validated as), and use it as such in their published studies:

  1. An Examination of Internet Pornography Usage among Male Students at Evangelical Christian Colleges (2011)
  2. Questionnaires and scales for the evaluation of the online sexual activities: A review of 20 years of research (2014)
  3. Problematic cybersex: Conceptualization, assessment, and treatment (2015)
  4. Clarifying the Links Among Online Gaming, Internet Use, Drinking Motives, and Online Pornography Use (2015)
  5. Cyberpornography: Time Use, Perceived Addiction, Sexual Functioning, and Sexual Satisfaction (2016)
  6. Examining Correlates of Problematic Internet Pornography Use Among University Student (2016)

The last study above used a longer version of the Grubbs CPUI and an Internet pornography addiction questionnaire derived from the DSM-5 Internet video-gaming addiction criteria. The graphs below show the same subjects' scores on the two different porn addiction questionnaires:


No surprise: very similar results and distribution for the Grubbs CPUI and the researchers' DSM-5-based porn addiction questionnaire. If the CPUI could differentiate "perceived addiction" from "actual addiction" the graphs and distributions would be sharply dissimilar. They are not.

Suggestion: whenever you read a Grubbs paper or a Grubbs sound-bite in the media, eliminate the word "perceived" and see how differently it reads - and how it aligns with other research on porn addiction. For example, two sentences from the introduction of a Grubbs's paper with the word "perceived" deleted:

Addiction to Internet pornography is associated with lower levels of well-being. Recent research has found porn addiction to be related to anxiety, depression, and stress (Grubbs, Stauner, Exline, Pargament, & Lindberg, 2015; Grubbs, Volk et al., 2015).

Eliminate the unsupported claim that the CPUI assesses "perceived porn addiction" and we have completely different study results and no misleading headlines. Again, such actual findings of porn addiction being associated with anxiety, depression and stress align with decades of "actual," not "perceived," addiction research. Inability to control use is distressing.

SECTION 2: Claimed Correlations? "Hours of use" and "Religiosity"

Contrary to Grubbs's claim the amount of porn viewed is significantly related to porn addiction scores (CPUI)

While we will see that "hours of use" is never used as the sole proxy for addiction, media sound-bites claim that Grubbs found no relationship between "hours of porn use" and scores on the porn addiction test (CPUI). This is not the case. Let's start with Grubb's 2013 study that decreed (by fiat) the CPUI-9 a "perceived porn addiction" test:

"Scores on the total CPUI-9, the compulsivity subscale, and the access efforts subscale were all associated with increased use of online pornography, indicating that perceived addiction [total CPUI score] is related to greater frequency of use."

Remember "perceived addiction" is shorthand for the total CPUI score. As described earlier, this 2015 Grubbs study reported a pretty strong correlation between hours of use and CPUI scores. From p. 6 of the study:

"Additionally, average daily pornography use in hours was significantly and positively associated with depression, anxiety, and anger, as well as with perceived addiction [total CPUI score]."

In other words, contrary to the headlines and Grubbs's claims in the press, subjects' total CPUI-9 scores were significantly associated with hours of porn use. But how does "average daily pornography use in hours" compare with religiosity? Which is more correlated with the CPUI- total score?

We will use data from a 2015 Grubbs paper ("Transgression as Addiction: Religiosity and Moral Disapproval as Predictors of Perceived Addiction to Pornography"), as it contains 3 separate studies and its provocative title suggests that religiosity causes porn addiction. Table 2 below contains data from 2 separate studies. These data reveal correlations between a few variables (hours of porn use; religiosity) and CPUI scores (entire CPUI-9 and broken down into the 3 CPUI subsections).

Tips for understanding the numbers in the table: zero means no correlation between two variables; 1.00 means a complete correlation between two variables. The bigger the number the stronger the correlation between the 2 variables. If a number has a minus sign, it means there's a negative correlation between two things. (For example, there's a negative correlation between exercise and heart disease. Thus, in normal language, exercise reduces the chances of heart disease. On the other hand, obesity has a positive correlation with heart disease.)

Highlighted below are the correlations between total CPUI-9 scores (#1) and "Use In Hours" (#5) and the "Religiosity Index" (#6) for two of Grubbs's studies:












The correlations between total CPUI scores and religiosity:

  • Study 1: 0.25
  • Study 2: 0.35
    • Average: 0.30

The correlations between total CPUI scores and "hours of porn use":

  • Study 1: 0.30
  • Study 2: 0.32
    • Average 0.31

Shockingly, CPUI-9 scores have a slightly stronger relationship to "hours of porn use" than to religiosity! Put simply "hours of porn use" predicts porn addiction better than does religiosity. Yet the study's abstract assures us that religiosity is "robustly related to perceived addiction" (CPUI scores). If this is the case, then "hours of porn use" are evidently also "robustly related" to scores on the CPUI. It's curious how religiosity's relationship to porn addiction is emphasized, while hours of use is overlooked or hidden by doublespeak.

There's no other way to say this - Grubbs's data flat out contradict his claims in the media and in his studies' abstracts. To refresh your memory, Grubbs's claims in this Psychology Today feature article:

Being labeled "porn addict" by a partner, or even by oneself, has nothing to do with the amount of porn a man views, says Joshua Grubbs, assistant professor of psychology at Bowling Green University. Instead, it has everything to do with religiosity...

In reality, the opposite is true: porn addiction is more related to hours of use than to religiosity. The next section will reveal that actual "porn addiction," as measured by CPUI questions 1-6, is far more related to "hours of porn use" than it is to religiosity.

Grubbs's studies reveal that actual porn addiction is far more related to "hours of porn use" than to religiosity

Grubbs found that porn addiction (CPUI-9 total score) is more strongly correlated with "current hours of porn use" than to religiosity. But you may be thinking, "Grubbs was right about one claim: porn addiction (CPUI scores) is related to religiosity." Not really. In the next section we will see why this claim is not what it seems.

Sticking with Grubbs's numbers for now, there is a relationship between actual porn addiction and religiosity. However, it's far weaker than indicated in the previous section. Just as important, the correlation between actual porn addiction and "hours of porn use" is far stronger than indicated in the previous section.

On closer examination, questions 1-6 of the CPUI-9 assess the signs and symptoms common to all addictions, while questions 7-9 (Emotional Distress) assess guilt, shame and remorse. As a result, "actual addiction" closely aligns with questions 1-6 (Compulsivity & Access Efforts).


  1. I believe I am addicted to Internet pornography.
  2. I feel unable to stop my use of online pornography.
  3. Even when I do not want to view pornography online, I feel drawn to it

Access Efforts:

  1. At times, I try to arrange my schedule so that I will be able to be alone in order to view pornography.
  2. I have refused to go out with friends or attend certain social functions to have the opportunity to view pornography.
  3. I have put off important priorities to view pornography.

Emotional Distress:

  1. I feel ashamed after viewing pornography online.
  2. I feel depressed after viewing pornography online.
  3. I feel sick after viewing pornography online.

First, let's examine the correlations between each of the 3 CPUI subsections and Religiosity. In the following table the three CPUI subsections are numbered 2, 3 and 4, and the Religiosity Index is number 6.












The correlation between Religiosity and Perceived Compulsivity (questions 1-3)

  • Study 1: 0.25
  • Study 2: 0.14
    • Average: 0.195

 The correlation between Religiosity and Access Efforts (questions 4-6)

  • Study 1: 0.03
  • Study 2: 0.11
    • Average: 0.07

The correlation between Religiosity and Emotional Distress (questions 7-9)

  • Study 1: 0.32
  • Study 2: 0.45
    • Average: 0.385

The key finding is that religiosity is strongly related (.39) to only the Emotional Distress section of the CPUI-9: questions 7-9, which asks porn users how they feel after viewing porn (ashamed, depressed, or sick). Religion is far less related to the two sub-sections (questions 1-6) that most accurately assess actual porn addiction: Compulsivity (.195) and Access Efforts (.07). Simplified: the shame and guilt questions (7-9) powerfully skew the total CPUI scores upward for religious individuals. Take away the 3 shame questions and the correlation between religiosity and the CPUI drops to a mere 0.13.

Examining the actual-addiction CPUI questions, it's evident that the 3 "Access Efforts" questions 4-6 assess principal addiction criteria for any addiction: "The inability to stop despite severe negative consequences." Compulsive use is a hallmark of addiction.

In contrast, question #1 in the Compulsivity section relies on subjective interpretation ("Do I feel addicted?").

Now, back to those Access Efforts questions 4-6, which assess specific behaviors, not beliefs or feelings. The key takeaway: there's an extremely weak correlation between Religiosity and the 3 Access Efforts questions (only 0.07). In summary, religiosity has very little relationship with actual porn addiction. (In fact, there's good reason to suggest there is virtually no relationship as we will see in the next section.)

Next, let's examine the correlations between each of the 3 CPUI subsections and "Hours of Porn Use." In the following table the three CPUI subsections are numbered 2, 3 and 4, and "[Porn] Use In Hours" is number 5.












The correlation between "[Porn] Use In Hours" and Perceived Compulsivity (questions 1-3)

  • Study 1: 0.25
  • Study 2: 0.32
    • Average: 0.29

 The correlation between "[Porn] Use In Hours" and Access Efforts (questions 4-6)

  • Study 1: 0.39
  • Study 2: 0.49
    • Average: 0.44

The correlation between "[Porn] Use In Hours" and Emotional Distress (questions 7-9)

  • Study 1: 0.17
  • Study 2: 0.04
    • Average: 0.10

This is the exact opposite of what we saw with religiosity. "[Porn] Use In Hours" correlates very strongly with the CPUI questions (1-6), which, again, most accurately assess actual porn addiction (0.365). More importantly, "[Porn] Use In Hours" correlate even more strongly with the CPUI's core addiction questions 4-6 (0.44). This means that actual porn addiction (as assessed by behaviors) is robustly related to how much porn a person views.

On the other hand, "[Porn] Use In Hours" is weakly related (0.10) to the "Emotional Distress" questions (7-9). These 3 questions ask porn users how they feel after viewing porn (ashamed, depressed, or sick). In summary, actual porn addiction (1-6) is strongly related to the amount of porn viewed, yet shame and guilt (7-9) are not. To put this another way, porn addiction has a whole lot to do with how much porn is viewed, and very little to do with shame (religious or otherwise).

Summary of Grubbs's actual findings

  1. Total CPUI-9 scores were better correlated with "[Porn] Use In Hours" than with religiosity. This finding directly contradicts claims in the media by Joshua Grubbs.
  2. Removing the 3 "Emotional Distress" questions leads to an even stronger relationship between "[Porn] Use In Hours" and actual porn addiction as assessed by questions 1-6.
  3. Removing the 3 "Emotional Distress" questions (which assess shame and guilt) leads to a much weaker relationship between religiosity and actual porn addiction as assessed by questions 1-6.
  4. A very strong relationship exists between "hours of porn use" and the core addiction behaviors as assessed by the "Access Efforts" questions 4-6. Put simply: porn addiction is very strongly related to amount of porn viewed.
  5. The relationship between "religiosity" and the core addiction behaviors (Access Efforts questions 4-6) is virtually non-existent (0.07). Put simply: addiction-related behaviors, rather than religiosity, predict porn addiction. Religiosity has next to nothing to do with porn addiction.  

Here's what a more accurate conclusion in Grubbs's study might have looked like:

Actual porn addiction is robustly related to hours of porn use and very weakly related to religiosity. Hours of porn use is a far better predictor of actual porn addiction than is religiosity. Why religiosity has any relationship to porn addiction is unknown. It could be the result of a skewed sample. When compared to non-religious individuals, a far lower percentage of religious individuals regularly view pornography. Perhaps this skewed sample of "religious porn users" contains a far higher percentage of individuals with pre-existing conditions (OCD, ADHD, depression, bipolar disorder, etc.) or familial/genetic influences commonly associated with addiction.

Finally, a recent study (by a non-Grubbs team) examined the relationships between pornography use and sexual satisfaction/functioning employing the CPUI-9. The study found that the amount of porn used was robustly related to questions 1-6 (0.50), yet not at all related to questions 7-9 (0.03). This means that the amount of porn used is a very strong factor in the development of a porn addiction. On the other hand, shame and guilt were not associated with porn use, and had nothing to do with porn addiction.

Studies recognize that amount of porn use is not linearly related to porn addiction

As explained above, the amount of porn used is far more related to actual porn addiction than is religiosity. That said, we need to address Grubbs's insinuation that hours of porn use is synonymous with "real porn addiction." That is, that the extent of a "genuine porn addiction" is best indicated simply by "current hours of internet porn viewing," rather than by standard porn addiction tests or by porn-induced symptoms. 

The hole in these author's underpinnings, which you could drive a truck through, is that research on internet porn and internet addictions (1, 2, 3, 4, 5, 6, 7, 8, 9) has reported that internet addiction sub-types do not correlate linearly with hours of use. In fact, the variable 'hours of use' is an unreliable measure of addiction. Established addiction assessment tools evaluate addiction using multiple other, more reliable factors (such as those listed in the first two sections of the CPUI). The following cybersex addiction studies, which Grubbs omitted, report little relationship between hours and indications of addiction:

1) Watching Pornographic Pictures on the Internet: Role of Sexual Arousal Ratings and Psychological-Psychiatric Symptoms for Using Internet Sex Sites Excessively (2011)

"Results indicate that self-reported problems in daily life linked to online sexual activities were predicted by subjective sexual arousal ratings of the pornographic material, global severity of psychological symptoms, and the number of sex applications used when being on Internet sex sites in daily life, while the time spent on Internet sex sites (minutes per day) did not significantly contribute to explanation of variance in Internet Addiction Test sex score (IATsex). We see some parallels between cognitive and brain mechanisms potentially contributing to the maintenance of excessive cybersex and those described for individuals with substance dependence."

2) Sexual Excitability and Dysfunctional Coping Determine Cybersex Addiction in Homosexual Males (2015)

"Recent findings have demonstrated an association between CyberSex Addiction (CA) severity and indicators of sexual excitability, and that coping by sexual behaviors mediated the relationship between sexual excitability and CA symptoms. Results showed strong correlations between CA symptoms and indicators of sexual arousal and sexual excitability, coping by sexual behaviors, and psychological symptoms. CyberSex Addiction was not associated with offline sexual behaviors and weekly cybersex use time."

3) What Matters: Quantity or Quality of Pornography Use? Psychological and Behavioral Factors of Seeking Treatment for Problematic Pornography Use (2016)

According to our best knowledge this study is the first direct examination of associations between the frequency of porn use and actual behavior of treatment-seeking for problematic porn use (measured as visiting the psychologist, psychiatrist or sexologist for this purpose). Our results indicate that the future studies, and treatment, in this field should focus more on impact of porn use on the life of an individual (quality) rather than its mere frequency (quantity), as the negative symptoms associated with porn use (rather than porn use frequency ) are the most significant predictor of treatment-seeking behavior.

Relation between PU and negative symptoms was significant and mediated by self-reported, subjective religiosity (weak, partial mediation) among non-treatment seekers. Among treatment-seekers religiosity is not related to negative symptoms.

4) Examining Correlates of Problematic Internet Pornography Use Among University Student (2016)

Higher scores on addictive measures of internet porn use were correlated with daily or more frequent use of internet porn. However, the results indicate that there was no direct link between the amount and frequency of an individual’s pornography use and struggles with anxiety, depression, and life and relationship satisfaction. Significant correlations to high internet porn addiction scores included an early first exposure to internet porn, addiction to video games, and being male. While some positive effects of internet porn use have been documented in previous literature our results do not indicate that psychosocial functioning improves with moderate or casual use of internet porn.

5) Viewing Internet Pornography: For Whom is it Problematic, How, and Why? (2009)

This study investigated the prevalence of problematic Internet pornography viewing, how it is problematic, and the psychological processes that underlie the problem in a sample of 84 college-age males using an anonymous online survey. It was found that approximately 20%–60% of the sample who view pornography find it to be problematic depending on the domain of interest. In this study, the amount of viewing did not predict the level of problems experienced.

Thus, from the outset this study and its assertions collapse because its conclusions rest upon equating current hours of use with the level of addiction/problems/distress reported by subjects as a valid measure of addiction. 

Why don't addiction specialists rely solely on hours of use?

Imagine trying to assess the presence of addiction by simply asking, "How many hours do you currently spend eating (food addiction)?" or "How many hours do you spend gambling (gambling addition)?" or "How many hours do you spend drinking (alcoholism)?" To demonstrate how problematic "hours of use" would be as an indicator of addiction, consider alcohol as an example:

  1. A 45-year old Italian man has a tradition of drinking 2 glasses of wine every night with dinner. His meal is with his extended family and it takes 3 hours to complete (lots of yakking). So he drinks for 3 hours a night, 21 hour per week.
  2. A 25 year-old factory worker only drinks on the weekends, but binge drinks both Friday and Saturday night to the point of passing out or getting sick. He regrets his actions and wants to stop, but can't, drives drunk, gets in fights, is sexually aggressive, etc. He then spends all of Sunday recovering, and feels like crap until Wednesday. However, he spent only 8 hours a week drinking.

Which drinker has a problem? How helpful is applying "hours of use" to gambling addiction? Take these two gamblers;

  1. A retired elementary school teacher who lives in Las Vegas. She and three of her friends regularly spend weekday afternoons on the strip playing nickel slot machines and video-poker at various non-smoking casinos. Afterwards they usually eat dinner at the CircusCircus $9.99 buffet. Total losses could be as high as $5.00, but they often break even. Total time per week - 25 hours.
  2. A 43-year old electrician with 3 teenage kids, who is now living alone in a seedy motel. Betting on the ponies has led to divorce, lost jobs, bankruptcy, inability to pay child support, and the loss of visitation rights. While he only visits the track 3 times a week, about 2 hours each time, his compulsive gambling ruined his life. He can't stop and is contemplating suicide. Total time gambling per week - 6 hours.

But, you wonder, surely the amount of drug used must equate to the level of addiction? Not necessarily. For example, millions of Americans with chronic pain are users of prescription opioids (Vicodin, Oxycontin) on a regular basis. Their brains and tissues have become physically dependent on them, and immediate cessation of use could cause severe withdrawals symptoms. However, very few chronic pain patients are addicted. Addiction involves multiple well-indentified brain changes that lead to the signs and symptoms experts recognize as addiction. (If the distinction is unclear, I recommend this simple explanation by NIDA.) The vast majority of chronic pain patients would happily throw away their narcotics in exchange for a life free of debilitating pain. This is quite different from true opioid addicts who often risk everything to continue their addiction.

Neither "current hours of use" nor "the amount used" alone can inform us as to who is addicted and who is not. There's a reason why "continued use despite severe negative consequences" helps experts define addiction, and "current hours of use" does not. Remember, the 3 "Access Efforts" CPUI questions assessed "the inability to stop despite severe negative consequences." In Grubbs's data, these questions were the strongest predictors of actual porn addiction.

Bottom line: Grubbs's claims depend upon "current hours of use" being the sole valid criterion for true addiction. They are not. Even if hours of use were a proxy for addiction, Grubbs's full studies reveal that "current hours of porn use" is strongly related to total CPUI-9 scores (i.e., "perceived" addiction). More importantly, "hours of porn use" is far more related to actual porn addiction (CPUI questions 1-6) than it is to religiosity.  So Grubbs's conclusions are both untrue and not based on existing addiction science.

"Current hours of porn use" omits many variables

A secondary methodological problem is that Grubbs assessed porn use by asking subjects about their "current hours of porn use." That question is troublingly vague. Over what period? One subject may be thinking "How much did I use yesterday?" another "over the last week?" or "on average since I decided to quit viewing because of unwanted effects?" The result is data that are not comparable and cannot be analyzed for the purpose of drawing reliable conclusions, let alone the vast, unsupported conclusions Grubbs draws.

More important, the "current porn use" question, on which the study's conclusions rest, fails to ask about key variables of porn use: age use began, years of use, whether the user escalated to novel genres of porn or developed unexpected porn fetishes, the ratio of ejaculation with porn to ejaculation without it, amount of sex with a real partner, and so forth. Those questions would likely enlighten us more about who really has a problem with porn use than simply "current hours of use."

SECTION 3: Is Religiosity Related to Actual Porn Addiction?

Introduction: Anecdotal evidence from sex therapists suggests there are clients who feel addicted to porn, yet view it only occasionally. It's possible that some of these clients are religious and experience guilt and shame surrounding their occasional porn use. Are these individuals suffering only from "perceived addiction" and not real porn addiction? Perhaps. That said, these individuals want to stop yet they continue to use porn. Whether or not these "occasional porn users" are truly addicted or just feeling guilt and shame, one thing is for sure: the Grubbs CPUI cannot distinguish "perceived addiction" from actual addiction in these individuals or anyone else.

One third of CPUI questions assess remorse and shame, resulting in higher scores for religious individuals

Because the last 3 of the 9 CPUI questions assess guilt, shame and remorse, religious porn users' CPUI scores tend to be skewed upward. For example, if an atheist and devout Christian have identical scores on CPUI questions 1-6, it's almost certain that the Christian will end up with far higher CPUI-9 scores, after questions 7-9 are added.

  1. I feel ashamed after viewing pornography online.
  2. I feel depressed after viewing pornography online.
  3. I feel sick after viewing pornography online.

Grubbs's actual findings are that religious porn users may feel more guilt about porn use (questions 7-9), but they are not any more addicted (questions 4-6).

In the end, all we can take from Grubbs's studies is that some religious porn users experience regret and shame. No surprise there. Since a much lower percentage of religious individuals use porn, Grubb's findings tell us nothing about religious people as a whole. The key point: Grubbs is using a skewed sample of religious subjects - the porn using minority - to claim that porn addiction is related to religiosity.

It's important to note that assessment questionnaires for other types of addiction rarely have questions about guilt and shame. Certainly, none make one third of their questionnaires about guilt and shame. For example, the DSM-5 criteria from Alcohol Use Disorder contain 11 questions. Yet none of the questions assess remorse or guilt after a drinking binge. Nor does the DSM-5 Gambling Addiction questionnaire contain a single question about remorse, guilt or shame. Rather, both of these DSM-5 addiction questionnaires emphasize dysfunctional behaviors, similar to questions 4-6 of the CPUI-9:

  1. At times, I try to arrange my schedule so that I will be able to be alone in order to view pornography.
  2. I have refused to go out with friends or attend certain social functions to have the opportunity to view pornography.
  3. I have put off important priorities to view pornography.

Remember, CPUI questions 4-6 are far more related to current "Hours of Porn Use" than any other factor (0.44). Meaning that "hours of use" is by far the strongest predictor of actual porn addiction in Grubbs's data. On the other hand, questions 4-6 bore very little relation to "religiosity" (0.07). Meaning that religiosity is not really related to porn addiction. The very small relation between religiosity and actual porn addiction are likely better explained by Grubb's s skewed sample and other factors discussed below.

Religiosity does NOT predict porn addiction. Not even a wee bit.

In Section 2 we pointed out that "hours of porn use" was more related to total CPUI-9 scores than was religiosity. Or as a researcher might say: "hours of porn use" predicted porn addiction slightly better than did religiosity. We also pointed out that the correlation between actual porn addiction (CPUI questions 4-6) and Religiosity averaged 0.07, while the correlation actual porn addiction (CPUI questions 4-6) and "hours of porn use" was 0.44. To put it another way: "hours of porn use" predicted porn addiction 600+% more strongly than did religiosity.

That said, Grubbs still reports a weak positive relationship between religiosity and core addiction questions 4-6 (0.07). So is Grubbs is right, that religiosity predicts porn addiction? No, religiosity does not predict porn addiction. Quite the opposite. Religious individuals are far less likely to use porn and thus less likely to become porn addicts.

Grubbs's studies did not use a cross-section of religious individuals. Instead, only current porn users (religious or nonreligious) were questioned. The preponderance of studies report far lower rates of porn use in religious individuals as compared with non-religious individuals (study 1, study 2, study 3, study 4, study 5, study 6, study 7, study 8, study 9, study 10, study 11, study 12, study 13, study 14, study 15, study 16, study 17, study 18, study 19, study 20, study 21, study 22, study 24)

Grubbs's sample of religious porn users is therefore skewed to the small percentage of religious men using porn. Put simply, religiosity is protective against porn addiction.

As an example, this 2011 study (The Cyber Pornography Use Inventory: Comparing a Religious and Secular Sample) reported the percentage of religious and secular college men who used porn at least once a week:

  • Secular: 54%
  • Religious: 19%

Another study on college aged religious men (I believe it is wrong but I still do it - A comparison of religious young men who do versus do not use pornography, 2010) revealed that:

  • 65% of religious young men reported viewing no pornography in the past 12 months
  • 8.6% reported viewing two or three days per month
  • 8.6% reported viewing daily or every other day

In contrast, cross-sectional studies of college-age men report relatively high rates of porn viewing (US - 2008: 87%, China - 2012: 86%, Netherlands - 2013 (age 16) - 73%). In short, given that a large majority of college-age, religious men rarely views porn, Grubbs's targeted sample of "religious porn users" is quite skewed, while his sample of "secular porn users" is fairly representative.

Now we turn to a few reasons why religious porn users might score higher on porn addiction questionnaires.

#1) Religious porn users are likely to have higher rates of pre-existing conditions

Given that a large majority of college-age, religious men rarely views porn, the Grubbs and Leonhardt, et al. targeted samples of "religious porn users" represented a small minority of the religious population. In contrast, samples of "secular porn users" tend to represent the majority of the non-religious population.

Most young religious porn users say they would rather not watch porn (100% in this study). So why do these particular users watch? It's extremely likely that the non-representative sample of "religious porn users" contains a far higher percentage of the slice of the entire population that struggles with the pre-existing conditions or comorbidities. These conditions are often present in addicts (i.e. OCD, depression, anxiety, social anxiety disorder, ADHD, family histories of addiction, childhood trauma or sexual abuse, other addictions, etc.).

This factor alone could explain why religious porn users, as a group, score slightly higher on the Grubbs porn addiction questionnaire. This hypothesis is supported by studies on treatment seeking porn /sex addicts (whom we could expect to hail disproportionately from that same disadvantaged slice). Treatment seekers reveal no relationship between religiosity and measurements of addiction and religiosity (2016 study 1, 2016 study 2). If Grubbs's conclusions were valid, we'd surely see a disproportionate number of religious porn users seeking treatment. This hypothesis is supported by studies on treatment seeking porn /sex addicts which reveal no relationship between religiosity and measurements of addiction and religiosity (2016 study 1, 2016 study 2).

#2) At high levels of porn use religious individuals return to religious practices and religion becomes more important

This 2016 study on religious porn users reported an odd finding that by itself could explain Grubbs's slight correlation between actual porn addiction and religiosity. The relationship between porn use and religiosity is curvilinear. As porn use increases, religious practice and the importance of religion decrease - up to point. Yet when a religious individual begins using porn once or twice a week this pattern reverses itself: The porn user starts attending church more often and the importance of religion in his life increases. An excerpt from the study:

"However, the effect of earlier pornography use on later religious service attendance and prayer was curvilinear: Religious service attendance and prayer decline to a point and then increase at higher levels of pornography viewing."

This graph, taken from this study, compares religious service attendance with the amount of porn used:















It seems likely that as religious individuals' porn use grows increasingly out of control, they return to religion as a means to address their problematic behavior. This is no surprise, as many addiction recovery groups based on the 12-steps include a spiritual or religious component. The author of the paper suggested this as a possible explanation:

...studies of addiction suggest that those who feel helpless in their addiction often elicit supernatural help. Indeed, twelve-step programs that seek to help persons struggling with addictions ubiquitously include teachings about surrendering to a higher power, and a rising number of conservative Christian twelve-step programs make this connection even more explicit.  It could very well be that persons who use pornography at the most extreme levels (i.e., use levels that might be characteristic of a compulsion or addiction) are actually pushed toward religion over time rather than pulled away from it.

This phenomenon of religious porn users returning to their faiths as addiction worsens could easily explain the slight correlation between actual porn addiction and religiosity.

#3) In contrast to religious subjects, secular porn using subjects may not recognize porn's effects because they never try to quit

Is it possible that religious porn users score higher on porn addiction questionnaires because they've actually tried to quit, unlike their secular brethren? In doing so they would be more likely to recognize the signs and symptoms of porn addiction as assessed by the Leonhardt, et al. 5-item questionnaire.

Based on years of monitoring porn recovery forums online, we suggest that researchers should segregate users who have experimented with quitting porn from those who haven't, when asking them about porn's self-perceived effects. It is generally the case that today's porn users (both religious and nonreligious) have little understanding of internet porn's effects on them until after they attempt to quit (and pass through any withdrawal symptoms).

In general, agnostic porn users believe porn use is harmless, so they have no motivation to quit...until they run into intolerable symptoms (perhaps, debilitating social anxiety, inability to have sex with a real partner or escalation to content they find confusing/disturbing or too risky). Prior to that turning point, if you ask them about their porn use, they will report that all is well. They naturally assume they are "casual users," who could quit anytime, and that symptoms they have, if any, are due to something else. Shame? Nope.

In contrast, most religious porn users have been warned that porn use is risky. They are therefore more likely to have used less porn and to have experimented with giving it up, perhaps more than once. Such experiments with quitting internet porn are very enlightening, as that is when porn users (religious or not) discover:

  1. How difficult it is to quit (if they're addicted)
  2. How porn use has affected them adversely, emotionally, sexually and otherwise (often because symptoms begin to recede after quitting)
  3. [In the case of such symptoms] How withdrawal can make symptoms worse for a while, before the brain returns to balance
  4. How bad it feels when they want to give something up and can't (This is shame, but not necessarily "religious/sexual shame" - as researchers sometimes assume because religious users report it more often. Most all addicts unfortunately feel shame when they feel powerless to quit, whether or not they are religious.)
  5. That they experience strong cravings to use porn. Cravings often increase in severity with a week or longer break from using porn.

Such experiences make those who have tried quitting far more wary about porn use. Since more religious users will more frequently have made such experiments, psychological instruments will show that they are more concerned about their porn use than non-religious users - even though they are likely using less porn!

In other words, shouldn't researchers also be investigating whether secular porn users sometimes misperceive porn use as harmless, rather than assuming it's the religious people who are misperceiving the existence of porn-related problems even though they're using less? Addiction, after all, is not assessed based on quantity or frequency of use, but rather debilitating effects.

In any case, the failure to segregate those who have experimented with quitting from those who have not, is a huge confound in research attempting to draw conclusions about the implications of the relationship between religiosity, shame and porn use. It's easy to misinterpret data as evidence that "religion makes people concerned about porn even if they're using less than others, and that if they weren't religious they wouldn't be concerned."

The more valid conclusion may be that those who have tried to quit, and realized the points above are more concerned, and that religion is merely the cause of their making such experiments (and otherwise largely irrelevant). It's disheartening to see psychologists make simplistic correlations with religion/spirituality and draw "shaming" conclusions, without realizing that they are comparing "apples" with "oranges" when they compare users who have tried to quit with users who haven't. Again, only the former tend to see the risks and harms of porn use clearly, whether or not they are religious.

This confound is too often exploited by those who want to draw attention away from the severe symptoms that non-religious users frequently experience. Agnostic users tend to have more severe symptoms by the time they do quit, simply because they tend to quit at a lower point in the downward spiral of symptoms than religious porn users do. Why aren't researchers studying this phenomenon?

In fact, we would wager that the lion's share of those with porn-induced sexual dysfunctions are agnostics. Why? Because the non-religious tend to be so persuaded of the harmlessness of internet porn use that they continue using it well past the warning signs, such as increasing social anxiety, escalation to extreme material, apathy, difficulty achieving an erection without porn, difficulty using condoms or climaxing with a partner, and so forth.

The fact is, even casual, or relatively infrequent, porn use can condition some users' sexuality such that it interferes with their sexual and relationship satisfaction. Here's one man's account. Escalation to porn content that was once uninteresting or repelling is common in half of internet porn users. In short, as discussed above, infrequent use is no panacea. Those who do not use frequently but are anxious about their porn use may have good reason to be concerned based on their own experiments, quite apart from what they hear about porn during religious services. 

Might it be better to construct research that asks porn users (both religious and otherwise) to quit porn for a time and compare their experiences with controls? See Eliminate Chronic Internet Pornography Use to Reveal Its Effects for a possible study design.

#4) The biological reasons why intermittent porn users might score higher on porn addiction questionnaires

Very frequent internet porn use has familiar risks for many of today’s users. These include escalation to more extreme material, poorer sexual and relationship satisfaction, addiction, and/or the gradual loss of attraction to real partners (as well as anorgasmia and unreliable erections).

Less well known is the fact that intermittent use (for example, 2 hours of porn bingeing followed by a few weeks of abstinence before another porn session) poses a substantial risk of addiction. The reasons are biological, and there is an entire body of addiction research on intermittent use in animals and humans elucidating the brain events responsible.

For example, both drug and junk food studies reveal that intermittent use can lead more quickly to addiction-related brain changes (whether or not the user slips into full blown addiction). The primary change is sensitization which blasts the brain’s reward center with signals that produce hard to ignore cravings. With sensitization, brain circuits involved in motivation and reward seeking become hyper-sensitive to memories or cues related to the addictive behavior. This deep pavlovian conditioning results in increased "wanting" or craving while liking or pleasure from the activity diminishes. Cues, such as turning on the computer, seeing a pop-up, or being alone, trigger intense cravings for porn. (Studies reporting sensitization or cue-reactivity in porn users: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20.)

Even more remarkable is that periods of abstinence (2-4 weeks) lead to neuroplastic changes that don’t occur in a user that doesn’t take such long breaks. These alterations in the brain increase cravings to use in response to triggers. Furthermore, the stress system changes such that even minor stress can cause cravings to use.

Intermittent consumption (especially in the form of a binge) can also produce severe withdrawal symptoms, such as lethargy, depression and cravings. In other words, when someone uses after an interim of abstinence, and binges, it can hit the user harder – perhaps because of the heightened intensity of the experience.

Based on this research, scientists have concluded that everyday consumption of say cocaine, alcohol, cigarettes, or junk food is not necessary to generate addiction-related brain changes. Intermittent bingeing can do the same thing as continuous use, and in some cases do more.

Now, let’s return to a comparison of religious and nonreligious porn users. Which group is likely to include more intermittent users? Given research showing that religious porn users prefer not to be using porn, there are probably more religious than secular users stuck in a binge-abstinence cycle. Religious users would tend to be “intermittent users.” Secular users generally report that they seldom take breaks of more than a few days – unless they become intermittent users because they are trying to quit porn use.

Another important effect of the binge-abstinence cycle is that intermittent porn users experience extended gaps (and often improvements). They can clearly see how their porn use has affected them, in contrast with frequent users. This alone might lead to higher scores on a porn addiction questionnaire. A second, more important result is that intermittent porn users will experience more frequent episodes of strong cravings. Third, when intermittent users do cave in, the science mentioned above predicts that they will often feel more out of control, and experience more of a letdown after the binge. In short, intermittent users can be quite addicted and score surprisingly high on porn addiction tests, even though they are using with less frequency than their secular brethren.

Under the circumstances, it is premature to conclude that shame accounts for the difference between religious and nonreligious users. Researchers must control for the impact of intermittent use. Said differently, if more of Leonhardt et al’s religious subjects included a higher percentage of intermittent users than their nonreligious subjects, one would expect the religious users to score higher on addiction tests despite using significantly less frequently.

Of course, the intermittent use addiction risk is not confined to religious porn users. This phenomenon shows up in animal models and secular porn users who are trying to quit but still bingeing occasionally. The point is that the phenomenon of intermittent use and porn addiction needs to be studied independently prior to drawing and publicizing assumptions about shame (or “perceived” pornography addiction) as the only possible explanation for why religious porn users report higher addiction scores in concert with less frequent use.

Summary of Religiosity and Porn Use:

  1. Religiosity does not predict porn addiction (perceived or otherwise). A far larger percentage of secular individuals use porn.
  2. Since a much smaller percentage of religious people use porn, religiosity is evidently protective against porn addiction.
  3. Grubbs and Leonhardt, et al. samples taken from the minority of "religious porn users" is skewed with respect to religious users, likely resulting in a much higher percentage of the religious sample having comorbidities. As a result religious porn users have slightly higher overall scores on porn-addiction instruments and report more difficulty controlling use.
  4. As porn use becomes frequent or compulsive, religious porn users return to their faiths. This means that those scoring highest on porn addiction tests will also score higher on religiosity.
  5. Most religious porn users have been warned that porn use is risky. They are therefore more likely to have used less porn and to have experimented with giving it up. In doing so they are more likely to recognize the signs and symptoms of porn addiction as assessed by the Grubss CPUI-9 of the Leonhardt, et al. 5-item questionnaire - regardless of amount of porn use.
  6. Intermittent porn users can be quite addicted and score surprisingly high on porn addiction tests, even though they are using with less frequency than their secular brethren.

SECTION 4: Grubbs Distorts the Current State of Addiction Research

The validity of internet pornography addiction is addressed in at least three of Joshua Grubbs's studies (Grubbs et al., 2015; Bradley et al., 2016; Grubbs et al., 2016.) All three papers casually toss aside decades of neuropsychological and other addiction research (and related assessment tools) to attempt to persuade readers that the scientific literature shows that internet porn addiction doesn't exist (thus supporting the Grubbs claim that all evidence of porn addiction must be "perceived," not real).

The studies Grubbs cited to dismiss porn addiction

In their opening paragraphs, Grubbs's three studies mentioned in the previous paragraph demonstrate their profound bias by basing their claim about the nonexistence of internet porn addiction on the papers of two self-proclaimed "internet porn addiction debunkers": David Ley, author of The Myth of Sex Addiction, and former UCLA researcher Nicole Prause, whose work has been formally criticized in the medical literature for weak methodology and unsupported conclusions. The three papers Grubbs believes debunk porn addiction:

  1. The Emperor Has No Clothes: A Review of the 'Pornography Addiction' Model (2014), by David Ley, Nicole Prause & Peter Finn
  2. Sexual Desire, Not Hypersexuality, is Related to Neurophysiological Responses Elicited by Sexual Images (2013), Vaughn R. Steele, Cameron Staley, Timothy Fong, Nicole Prause
  3. Viewing Sexual Stimuli Associated with Greater Sexual Responsiveness, Not Erectile Dysfunction (2015), Nicole Prause & Jim Pfaus

Paper #1 (Ley et al., 2013) is a one-sided propaganda piece by Ley, Prause and their colleague Peter Finn, which claimed to be a review of the porn addiction model. It was not. First, Ley et al. omitted all published studies showing ill effects from porn use on the grounds that they are "merely" correlational. You read that right. Secondly, it cherry-picked random, misleading lines from within studies, failing to report the researchers' actual opposing conclusions. Third, Ley et al. cited numerous studies that were entirely irrelevant to the claims made. We realize these are very strong assertions, yet they are fully supported and documented in this line-by-line critique. It should be noted that Ley et al. editor, Charles Moser, has long been a vocal critic of porn and sex addiction. Also know that Current Sexual Health Reports has a short and rocky history. It started publishing in 2004, and then went on hiatus in 2008, only to be resurrected in 2014, just in time to feature Ley et al.

Paper #2 (Steele et al., 2013) was an EEG study touted in the media as evidence against the existence of porn addiction. Not so. This SPAN Lab study actually lends support to the existence of both porn addiction and porn use down-regulating sexual desire. How so? The study reported higher EEG readings (P300) when subjects were briefly exposed to pornographic photos. Studies show that an elevated P300 occurs when addicts are exposed to cues (such as images) related to their addiction. However, due to methodological flaws the findings are uninterpretable: 1) subjects were heterogeneous (males, females, non-heterosexuals); 2) subjects were not screened for mental disorders or addictions; 3) study had no control group for comparison; 4) questionnaires were not validated for porn addiction. In line with the Cambridge University brain scan studies, this EEG study also reported greater cue-reactivity to porn correlating with less desire for partnered sex. Put another way, individuals with more brain activation and cravings for porn preferred to masturbate to porn than have sex with a real person. Study spokesperson Nicole Prause claimed that these porn users merely had high libido, yet the results of the study say the exact opposite (their desire for partnered sex was dropping in relation to their porn use). As neither result matched the concocted headlines, Grubbs perpetuated flawed conclusions of the original authors (the "debunkers of porn addiction"). Five peer-reviewed papers have formally analyzed Steele et al., 2013 concluding that its findings are consistent with the porn addiction model it claims to debunk: 1, 2, 3, 4, 5. Also see this extensive critique.

Paper #3 (Prause & Pfaus 2015) was presented by Grubbs as evidence for the positive effects of porn:

...some studies even suggest potentially positive outcomes associated with pornography use (Prause & Pfaus, 2015).

Prause and Pfaus wasn't a real study and it did not find "positive outcomes" related to porn use. None of the data from the Prause & Pfaus (2015) paper matched the four earlier studies on which it was based. The discrepancies were not small and have not been explained. A comment by researcher Richard A. Isenberg MD, published in Sexual Medicine Open Access, points out several (but not all) of the discrepancies, errors, and unsupported claims. The solitary positive outcome Prause & Pfaus claimed was a slightly higher "subjective arousal rating" after viewing porn in subjects who watched more porn at home. Several problems with this claim:

  1. The more science-based way to interpret this arousal difference is that the men who used more porn experienced greater cravings to use porn. Interestingly, they had less desire for sex with a partner and more desire to masturbate than those who logged fewer hours watching porn.
  2. Prause & Pfaus could not have accurately assessed the subjects' arousal because:
  • the underlying 4 studies used different types of porn. Two studies used a 3-minute film, one study used a 20-second film, and one study used still images.
  • the underlying 4 studies employed different number scales. One used a 0 to 7 scale, one used a 1 to 7 scale, and one study did not report sexual arousal ratings.

Richard A. Isenberg MD asked Prause & Pfaus to explain how they could claim this result in the absence of supporting data. Neither author has been able to provide a comprehensible answer.

What the Grubbs studies omitted

With respect to Grubbs's bias, it is even more telling that the 3 studies named above omit every neurological and neuropsychological study that found evidence in support of the porn addiction model (over 30 collected here). In addition, Grubbs omitted 12 recent reviews of literature on porn and sex addiction (in the same list). Many of these studies and reviews are by some the top neuroscientists at Yale University, Cambridge University, University of Duisburg-Essen, and the Max Planck Institute. (Some of these were not yet published when Grubbs's studies went to press, but many were, and were simply ignored.)

Contrast those eminent researchers with Ley and Prause. Ley has no background in neuroscience and had published nothing until Ley et al., 2014. Prause hasn't been associated with any university since December, 2014, and her claims surrounding her 2 EEG studies have been repeatedly discredited in the peer-reviewed literature (2015 study: 1, 2, 3, 4, 5, 6.; 2013 study: 1, 2, 3, 4, 5.)

We can speculate that acknowledging the existence of 35 neurological studies and 12 reviews of literature supporting the porn addiction model would severely undercut Grubbs's thesis that porn addiction....

"has everything to do with religiosity and moral attitudes toward sex. In short, he says, "It's shame-motivated."...

If "porn addiction is simply shame" how does Grubbs explain away the growing number of neurological studies that have found brain changes in problematic porn users that align with substance addiction? How could shame cause the same brain changes that occur with drug addiction? How could evidence of shame disprove the presence of addiction in brains showing evidence of addiction? It can't.

(both religious and otherwise) to quit porn for a time and compare their experiences with controls? See Eliminate Chronic Internet Pornography Use to Reveal Its Effects for a possible study design.