Marijuana Use & Brain Functioning in Young Adults

In the past decade, daily marijuana use by young adults has been steadily rising. “The rate at which college and non-college age adults use marijuana — 7.8 percent — is the highest it has been since the early 1980s,” an article in The Nation’s Health, a publication of the American Public Health Association explained in 2017. The main reasons for it’s increased popularity are the loosened laws for obtaining marijuana in many states, such as California and Colorado, and a cultural shift in attitudes towards using marijuana.

But studies have shown that regular marijuana use is not healthy for college students. Contrary to popular belief that marijuana can relieve stress, heavy use in young adults is associated with changes in the brain that impair a student’s motivation, anxiety levels and cognitive processing.

“‘We know from our research and that of others that heavy marijuana use is associated with poor academic performance and noncompletion of college...Marijuana use has remained steady in recent years among the nation’s high school seniors, so this increase among college students suggests it has something to do with college and young adulthood experiences,’” says John Schulenberg, PhD, in a follow-up study of the Monitoring the Future national survey from 2017.

Decreased functioning from marijuana use isn’t a sign of being lazy or relaxed - it’s the result of systemic impairment on brain development. One joint study between researchers from Northwestern University and Harvard Medical School compared MRI’s of students who had reported frequent marijuana use to those who had little or no history of marijuana use. The scans showed that the marijuana users showed a structural brain difference. “In particular, the nucleus accumbens—which is a brain region linked to reward processing and motivation—was larger and altered in its shape and structure in the marijuana users compared to non-users. Of particular interest to the researchers was that the nucleus accumbens was abnormally large, and its alteration in size, shape and density was directly correlated to how many joints an individual had smoked,” the study, outlined in Psychology Today, explained.

Daily Marijuana Use: Effects

While many studies have considered the deleterious effects of alcohol abuse on the young adult’s brain, only recently have the effects of marijuana use come to light. The cultural assumption is that marijuana use does not have long-term impact on brain functioning. Research disagrees. Adolescents and young adults who regularly smoked marijuana performed poorer on performance tests of learning, cognitive flexibility, visual scanning, error commission and working memory. This trend continues, as the more use over the course of a lifetime continues to lead to poorer cognitive functioning, a 2010 study published in the National Center for Biotechnology Information found.

These findings impact our perception of what it means to use marijuana. For the college student, learning is central to daily work, and stress from the various transitions from adolescence that college students face can make it especially difficult to concentrate. It is essential that college students understand the risks of using marijuana regularly and seek support, as its effects on their ability to succeed are real. Working with experts who understand the psychological effect of substance abuse on this specific population and who have worked as advocates for young adults in college with addiction can validate your experience and help you regain motivation to succeed.