College attendance became a dramatically stronger risk factor for marijuana initiation after 2013, with college students 51% more likely to start using marijuana than non-college peers in 2015.
Read this if you are a college student, parent of a college student, or college administrator concerned about marijuana use on campus.
College students were 51% more likely to start marijuana in 2015, up from 17-22% historically
What the researchers found
Using Monitoring the Future data tracking nationally representative cohorts from 1977 to 2015, this study examined college attendance as a risk factor for marijuana initiation among people who had never used marijuana by 12th grade.
For decades (1977-2012), college enrollment was associated with a modest 17-22% increased probability of starting marijuana use compared to non-college peers. But starting in 2013, this increased dramatically.
By 2013, the increased probability was 31%. By 2014, it was 41%. By 2015, college students who had never used marijuana by high school graduation were 51% more likely to start using than their non-college peers.
The year 2013 was identified as a watershed for increasing tolerance of marijuana use in the United States, coinciding with the implementation of recreational legalization in Colorado and Washington.
Why it matters
This reversal of the historical pattern, where college was only a modest risk factor, into a major risk factor for marijuana initiation signals a significant shift in the college environment. If this trend continues, colleges may need to develop new prevention and intervention programs.
The numbers in context
Increased probability of past-year marijuana use for college vs. non-college: 17-22% average from 1977-2012. Then: 31% in 2013, 41% in 2014, 51% in 2015.
How the study worked
Longitudinal panels from the Monitoring the Future study, following nationally representative 12th-grade samples from 1976 onward. Panel members aged 19-22 who had never used marijuana by 12th grade were analyzed for marijuana initiation. College enrollment status was assessed.
What this study cannot tell us
The study cannot establish causation between legalization and increased college marijuana initiation. Other cultural factors (social media, changing attitudes) occurred simultaneously. The analysis focuses on initiation, not problematic use or outcomes. Data end in 2015 and patterns may have continued to evolve.
How to read the evidence
Large nationally representative longitudinal study spanning nearly 40 years. Strong due to the Monitoring the Future study's rigorous methodology and representative sampling.
When this study was published
Published in 2017, covering data from 1977-2015.
The bigger picture
The timing aligns with broader cultural shifts in marijuana acceptance and the beginning of recreational legalization. College campuses, already characterized by experimentation and social influence, appear to have amplified these broader trends, creating a new risk environment for marijuana-naive students.
Questions still open
- Has the college risk factor continued to increase since 2015? Are specific college characteristics (size, location, culture) associated with higher initiation risk? Do colleges in legalized states show higher rates than those in non-legalized states?
Common questions
Is college a risk factor for starting marijuana?
Why did the risk increase after 2013?
Read the original research
The Influence of College Attendance on Risk for Marijuana Initiation in the United States: 1977 to 2015.
American journal of public health, 107(6), 996-1002
Citation
Miech, Richard A; Patrick, Megan E; O'Malley, Patrick M; Johnston, Lloyd D. (2017). The Influence of College Attendance on Risk for Marijuana Initiation in the United States: 1977 to 2015.. American journal of public health, 107(6), 996-1002. https://doi.org/10.2105/AJPH.2017.303745
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