Sharon Kirkey
Montreal researchers are reporting on the curious case of a Quebec man apparently cured of a cocaine addiction following a stroke.
Although it’s based on a single case report, the finding could set the foundation for more research into whether it’s possible to target and treat the underlying brain regions behind drug abuse, possibly with deep brain stimulation.
The case involves a 45-year-old man who had been addicted to cocaine since he was 24, injecting or snorting up to seven grams a day.
Twenty-one months ago, he experienced a stroke affecting the basal ganglia, large clusters of nerve cells located deep in the brain that receive dopamine — the neurotransmitter involved in the brain’s pleasure and reward system that’s important for addictive behaviors.
When people do something pleasurable, the brain releases a surge of dopamine that reinforces that behavior, said lead researcher Dr. Sylvain Lanthier, an associate professor at the University of Montreal and director of the neurovascular program at Centre hospitalier de l’Universite de Montreal.
Cocaine enhances the effects of dopamine, but it’s short-acting. “You have a big rush of dopamine, and then suddenly it goes away,” Lanthier said. “That’s why you feel the need to use again.”
In an abstract presented at the recent Canadian Stroke Congress in Calgary, Lanthier’s team reported that, “remarkably, (the man) reported no further craving for cocaine following stroke onset.”
He scored nine out of 10 on a drug abuse screening test pre-stroke, “indicating a severe level of problems related to drug use,” the researchers wrote, and a zero out of 10, post-stroke.
“The man doesn’t experience any craving, any sensation that he needs to take cocaine,” Lanthier said.
The patient experienced some temporary paralyses on his right side, but recovered rapidly. There were no lingering “deficits” or side effects, Lanthier reports, save for one: the man developed “micrographia”, abnormally small hand writing.
It’s believed to be the first reported case of cocaine addiction relieved by a stroke.
“It highlights the fact that certain areas of brain are very important for the experience of the ‘high’ that comes from cocaine and substance use,” says Dr. Mark Bayley, medical director of the brain and spinal cord rehabilitation program at the UHN-Toronto Rehab Institute
“It tells us that these neurotransmitters that are triggered by cocaine can be blocked.”
One way of blocking those pathways might be via deep brain stimulation, or DBS, an experimental treatment that uses electrical currents to reset the brain. DBS is being tested on patients with severe depression, Parkinson’s and Alzheimer’s disease.
Current addiction treatments primarily involve a combination of cognitive behavioral therapy, or talk therapy, and anti-depressants.
“We like to say in neurology that you learn neurology one stroke at a time,” said Dr. Michael Hill, director of the acute stroke unit at Foothills Medical Centre in Calgary.
“There are lots of examples where someone has a small stroke in just the right location to give them a specific change in behavior, or specific cognitive deficit.” Hill once saw an accountant who had a stroke while working on someone’s taxes. He suddenly could no longer add and subtract numbers.
“What’s novel about this (the Quebec case) is that it’s pretty unusual to have the circumstance where someone is a former abuser of illicit drugs and then has a stroke which impairs their desire to even consider taking those drugs again,” Hill said.
“It’s pretty cool. It helps us understand more about how these things work,” Hill said.
Different parts of the brain are responsible for different functions, he said. It’s not always the same in every person, but it’s similar enough that, “if there is a common location where people display addictive behaviors, it might be possible to modulate that with a stimulator.”
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