Your Brain on Porn Series - Part 3

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Sorry to cram so much onto a slide, but this is an addiction test, and I want you to have it all in one place. If you say “yes” to three or more of these questions, then you have an addiction—at least according to the American Psychiatric Association. I had to abridge it slightly, and the reality is that it’s used for substance abuse, not for porn addiction.
APA addiction test
If you say “yes” to two or fewer, you can stop reading and click to your favorite porn site.

“Tolerance” is a strange word, but it means, “Has your use increased or escalated over time?” So, if you watch porn, do you watch it for more hours? Or, have you escalated to more shocking or more extreme porn?

“Withdrawal” You can certainly have an addiction without withdrawal symptoms, but most users on our forum do experience some symptoms when they quit. Could be anxiety, irritability, fatigue, depression. Those are the most common. But some experience flu-like symptoms, headaches, insomnia, etc.

“Difficulty controlling use” Do you use porn for longer than you’d like to?

“Any negative consequences?” To your mood? To your health?

“Neglecting or postponing activities” Are you doing porn instead of life?

“Desire to cut down” Most addicts say they can quit any time. But they don’t. Have you tried unsuccessfully to cut down?

“Spending significant time or energy” Have you ever concealed your porn use? Probably everyone can say “yes” to that one.

It’s common knowledge that addictive substances like alcohol, cocaine or meth can cause brain changes that lead to addiction. But what about so-called “behavioral addictions,” such as food, gambling, sex, shopping or online video games? Do they cause brain changes that lead to addiction? Well, of course they do. That’s why they are addictions.

Recent research on gambling and food has shown brain changes that mimic those seen in drug addiction. Internet porn? No one wants to study it. Also, there hasn’t been time for much study, because it’s a very recent phenomenon.

Now, you tell me: Which is more stimulating? Eating cheesecake, or masturbating to Internet porn? It’s known that sex and masturbation raise dopamine levels far higher than eating. Which can you spend more time doing in a day—eating or edging to porn?

Let’s talk about natural reinforcers. “Natural reinforcer” is a fancy word for a non-drug activity that causes dopamine releases—such as food, sex, gambling, gaming.

Only about 15% of drug users (human or animal) ever become addicted. Obviously, genes are at work, as are childhood experiences. If you look at natural reinforcers, and of course food is a powerful one, you see a much higher percentage of people who can become addicted. (Among Americans, 66% overweight, 35% obese) Of course, it takes a lot longer than it typically does with addictive drugs.

Think about it. Few people want to be fat. Yet in modern Western cultures, most people are. Rats, on the other hand, don’t care if they’re fat. When they eat Western food, almost all of them overeat and become obese—not just fat.

This suggests two things about natural reinforcers:

1. Our reward circuitry evolved to drive us toward food and sex—and not drugs. This is why so many people can potentially get addicted to Internet porn.
2. Highly stimulating versions of food and sex can hook us—even when we’re not genetically susceptible to substance addictions.

Here’s the question: “When can natural reinforcers become addictive?”
1. When they’re a highly stimulating version of what our ancestors found irresistible.
2. When something is available in limitless supply.
3. When it is available in lots of varieties—that’s the lure of novelty.
4. We binge on it without realizing it is causing brain changes.

Modern food and Internet porn meet all four of these characteristics. Both can override our brain’s natural satiation mechanisms—that “I’m done” feeling. Remember, seeking calories and fertilization opportunities really are our gene’s top priorities. In other words, our limbic system’s top priorities.

If you have an addiction, your brain has adapted to overstimulation. Here’s what all addictions share:

1. A numbing of the reward circuitry, and
2. Rewiring of brain circuits

If you have a numbing of the reward circuitry, you’ve messed up your dopamine response in some way. It becomes harder to stimulate that part of your brain—whether with food, sex or rock ‘n’ roll. You simply feel less pleasure.

Feeling less pleasure leads to craving whatever will give you more pleasure—and that’s often your addiction. Your reward circuitry is basically like a flashlight with fading batteries.

There are two main aspects to rewiring of brain circuitry:

1. You get a stronger “go for it” signal. You’ve wired together a bunch of nerve cells that are screaming, “Let’s do that again! Let’s repeat that addictive behavior.” This adds to the cravings coming from the numbed reward circuitry. The more you use this circuitry, the stronger it gets—just like a muscle.
2. You also have a weaker control circuit in your brain. Just like a muscle that is under-exercised, this logical, rational circuit that understands consequences gets weaker. You know that drinking a bottle of whiskey or watching porn for hours a day may not be the best idea.

With an addiction, there’s a tug-of-war, and the “Go for it!” circuit is winning. To understand addiction, we need to understand what changes.
Nerve cells
What changes is nerve cells. In particular, what changes is connections between nerve cells. The brain contains billions of nerve cells, and they’re connected in circuits or pathways—such as the reward circuit, and endless other circuits.

When a circuit is activated, we have a thought, a feeling, an experience—which is specific to the circuit activated.

Nerve cells connect at a tiny little gap called a synapse. You have electricity that flowing along a nerve cell, but it stops at this gap. It causes the sending nerve cell to release neurochemicals—maybe dopamine—and these neurochemicals float over and attach to the receiving nerve cell. They attach to places called receptors. Study the picture, because receptors are important.
Nerve cell synapse
Receptors are like little “ears” on the receiving cell, which can hear particular messages that are being sent. There are many different neurochemicals in the brain, each with a different message.

If there are enough neurochemicals of a particular kind released from the sending cell, the receiving cell “hears” the message and fires an impulse. And we have an experience.

Why do we care about what goes on in this gap between nerve cells? This is where all addictions occur. Changes here, in the synapse, lead to a numbed pleasure response—and rewiring of the brain.

In this slide, nerve cells are communicating. You see dopamine being released (the red, round things) by the sending nerve cell. The receiving cell, here a reward nerve cell in the reward circuitry, is receiving the message, which is dopamine.
Nerve cell communication
So electricity flows along the nerve cells (the red arrows), and the more electricity coming from other parts of the brain, the more dopamine released. In the top images, you have a whole lot of dopamine released, because you have more impulses of electricity heading down the cell. This equates with a greater experience of excitement—perhaps heading toward orgasm. “I don’t want to stop!”

In the bottom image, hardly any dopamine is being released—perhaps after orgasm. “I just want to roll over and snore.” So the level of neurotransmitter, or dopamine, released equals the power of the message. Something like methamphetamine or cocaine causes a huge release of dopamine.

Back to the receptors at the synapse. The receptors “hear” the message. Some people think of them as little “ears” or “locks” for specific “keys.” In this case, dopamine is the key that unlocks these receptors. When that happens, the message continues along the receiving nerve cell. In this picture, the cells’ normal number of receptors are full of dopamine, so a “Go!” signal is being transmitted to the receiving cell.
Nerve cell communication relies on receptor density
You need all of those receptors activated by dopamine to get that message. With addiction, changes occur in the number of receptors.

The top image here (next image) shows a normal cell with the normal number of dopamine receptors (simplified here, of course). The reward circuitry can “hear” the message. The bottom image shows only a couple of receptors. This is what happens in all addictions. (D2 receptors, are the ones that actually drop in number.)
Nerve cell communication relies on receptor density
With overstimulation (i.e., junk food, Internet porn or drugs), the receiving cell says, “Enough is enough! I can’t handle all this dopamine.” It’s as if someone screams at you, and you cover your ears. Nerve cells accomplish this by getting rid of their dopamine receptors.

In other words you may have plenty of gas, or dopamine, to run your reward circuitry, but your engine is missing some of the cylinders: the receptors. Fewer dopamine receptors lead to a weakened response. That’s what you see in the bottom image. All addictions have this weakened sensitivity to dopamine in common.

Basically, your brain is crying out, “I need more dopamine to feel okay.” But there aren’t enough to receptors to hear the message. Literally, there’s not enough electricity flowing through the reward circuitry to make you feel okay. You have less pleasure from normal, everyday things—such as chocolate ice cream, foreplay, or watching your favorite TV show.

Low dopamine receptors lead to other symptoms, too, such as being tired, anxious, irritable or depressed. Until someone goes all the way through withdrawal and the dopamine receptor levels bounce back, they won’t experience normal levels of pleasure.

This is one of the main reasons addicts have such cravings. They’re looking for something to make them feel good again.



First of thank you for such a wonderful source of information, God bless you. Now to my question inside the synapse how many dopamine receptors are their in a healthy brain, and what is the amount of receptors that disappear due to an over-stimulation of the reward circuitry; in other word by what quantity would the amount of receptors go down by? Thank you in advance

to go into specifics about number of receptors, but percentages I've seen for food and Internet addiction suggest about 20% lower. However, addiction is far more than lowered D2 receptors in the striatum. Also have lower baseline dopamine, sensitized porn pathways, weak frontal cortex, disorganized myelin and abnormal stress response - and a whole lot more.