January 14, 2016

Even occasional and limited marijuana use during college may have negative effects on a student’s long-term physical and mental health, according to research led by Dr. Amelia Arria, Associate Professor in the Department of Behavioral and Community Health in the University of Maryland School of Public Health.

In a new study published in the international journal Drug and Alcohol Dependence, students evaluated over a nine-year period post-matriculation showed significant differences in health outcomes based on the course of their marijuana use during college.

Researchers used data from a 10-year study of a group of 1,253 young adults who were recruited as first-year college students in 2004, and assessed annually. In an earlier studyDr. Arria and colleagues identified six trajectories of marijuana use among participants after the seventh year: Non-Use, Low-Stable, Early-Decline, College-Peak, Late-Increase, and Chronic.

The team's most recent study found that participants who followed a trajectory of minimal or no marijuana use during the first six years of the study had significantly better health outcomes in their late 20s than most of the other trajectory groups. Similarly, individuals whose marijuana use declined over time appeared to have better mental health outcomes than their counterparts who maintained stable marijuana use into their late 20s. Chronic and Late-Increase marijuana users fared the worst, even accounting for background risk factors and related rates of change in alcohol and tobacco use. 

The findings also suggest that even taking up marijuana use at a later age may not protect users from adverse mental health outcomes.

Many studies have linked marijuana use to health outcomes in young people, but more research is needed to assess the long-term effects of college-age marijuana use, said Dr. Arria, who directs the Center on Young Adult Health and Development at the University of Maryland School of Public Health. She also serves as Principal Investigator on the College Life Study, a longitudinal prospective study of health-risk behaviors among college students. Her work focuses on the familial, social, and individual risk and resiliency factors associated with mental health and substance abuse among adolescents and young adults. 

“College is an opportune time to identify and intervene to prevent further escalation of use, or to prevent initiation,” Dr. Arria said. “Despite the popular notion that marijuana use is benign, students should realize that marijuana use can have adverse impacts on health and functioning, and can especially raise the risk of mental health problems.”

Related Links

Marijuana use trajectories during college predict health outcomes nine years post-matriculation

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Amelia Arria