New research from the University of California-San Diego School of Medicine has uncovered impaired neuronal activity in the brains of college-aged students who occasionally use stimulant drugs, such as amphetamines, cocaine and certain prescription drugs.
The research team, led by Katia Harlé, PhD, recently published their findings in the Journal of Neuroscience.
For their study, the investigators used functional magnetic resonance imaging (fMRI) to record the brain activity of 213 college students aged 18-24 years. Of these, 158 were occasional users of stimulant drugs, meaning they had taken stimulants an average of 12 to 15 times. The remaining 47 participants had never taken stimulants.
During fMRI, participants were required to take part in a test. They were shown either an X or an O on a screen and asked to press a left button when an X appeared, and a right button when an O appeared. They were instructed to press each button as quickly as possible.
In some tests, participants heard a tone, and this required them to avoid pressing either button. The investigators measured each subject's reaction times and errors during 288 tests.
Occasional stimulant users 'have impaired ability to anticipate a situation'
Results of the study revealed that students who were occasional stimulant users had faster reaction times during the tests, compared with those who had never taken stimulants. The investigators say this suggests that occasional stimulant users had a tendency to be more impulsive.
However, in the tests where a tone was applied later (indicating higher difficulty), occasional stimulant users made more errors and had overall worse performance than those who did not use stimulants.
When looking at the participants' brain scans, the researchers found that occasional stimulant users demonstrated consistent patterns of reduced neuronal activity in brain regions linked to anticipatory functioning and updating anticipation.
Explaining what these results mean, Harlé says:
"We used to think that drug addicts just did not hold themselves back, but this work suggests that the root of this is an impaired ability to anticipate a situation and to detect trends in when they need to stop."
Brain impairment may indicate risk of later-life drug addiction
The investigators say that these findings suggest that college-aged occasional stimulant users with these brain impairments may be more prone to drug addiction later in life.
College-aged students who occasionally used stimulant drugs showed impaired brain activity in regions linked to anticipation, which may put them at higher risk of later-life drug addiction.
But in a positive sense, the findings show that it may be possible to use brain activity patterns to predict whether youths are at risk of drug addiction before they fall into such behaviors.
"If you show me 100 college students and tell me which ones have taken stimulants a dozen times, I can tell you those students' brains are different," says Dr. Martin Paulus, professor of psychiatry at UCSD and co-senior author of the study.
"Our study is telling us, it's not 'this is your brain on drugs,' it's 'this is the brain that does drugs.'"
The research team now plans to carry out further investigation to find out whether the brain changes found in occasional stimulant users are permanent, or whether they can be returned to normal. They add that it could be possible to "exercise" these weak brain areas.
"Right now there are no treatments for stimulant addiction and the relapse rate is upward of 50%," says Dr. Paulus. "Early intervention is our best option."
Last year, Medical News Today reported on a study revealing how the stimulant cocaine prompts rapid growth in new brain structures linked to memory and learning, but in a way that encourages users to seek more of the drug.