Though marijuana is the most commonly used illegal drug in the country, little is definitively known about its impact on the brain.
A study taking place at Indiana University is designed to help change that.
Clinical psychologist Brian O’Donnell and colleague Sharlene Newman are recruiting current and former marijuana users to participate in a study in which their brains will be analyzed for changes in structure and function.
“From animal studies, there’s reason to believe it (marijuana use) will affect parts of the brain and also the connections between them, and some of our preliminary studies suggest that is the case,” said O’Donnell, a professor in the department of psychological and brain sciences.
The study — funded by a $275,000 grant from the National Institutes of Health — is taking place as marijuana gains acceptance in some parts of the country. Marijuana has been legalized for recreational use in Colorado, Washington state, Alaska and Oregon, and many states now have medical marijuana programs, according to the National Conference of State Legislatures.
“It’s being decriminalized, but without knowledge of really its long-term effects on brain structure or function,” O’Donnell said.
The Indiana researchers — who will use magnetic resonance imaging to conduct the study — are recruiting 90 people, ages 18-35, to participate in their research. Along with current and past users of marijuana, the study, which is one of the first of its type, will include people who’ve never used the drug.
“We’re comparing the subjects in the different groups,” said Newman, who’s an associate professor and the director of IU’s Brain Imaging Facility. “The group that’s never used marijuana is our baseline group.”
Former marijuana users are being studied because it’s possible that “smoking cannabis causes problems in the brain in terms of structure or in terms of function, but maybe people recover after they stop using it for a little while,” he said.
Study participants will undergo a series of brain scans so that the research team can do connectivity analysis.