Current research supports previous findings regarding alterations in the brains of adolescents and young adults who use alcohol or marijuana. These neuroadaptations in function and anatomy are associated with impaired decision making, memory and impulsivity in this population.

Currently, 4 out of 5 college students drink alcohol and half of these are binge drinkers. In addition, 58% of alcohol drinking adolescents report using alcohol and marijuana simultaneously. Yet there is a dearth of data regarding the concurrent use of these intoxicants—until now.

Data from the two-year Brain and Alcohol Research in College Students (BARCS) study included 1142 freshman students who completed monthly marijuana and alcohol consumption surveys. Based on the results, the students were classified into one of three data-driven groups based on their consumption: 1) no/low users of both, 2) medium-high alcohol/no-low marijuana, and 3) medium-high users of both substances.

The Analysis Was Sobering

Compared to sober peers, students using moderate to high levels of alcohol plus low marijuana use had lower GPAs, but this difference becomes non-significant over time. In contrast, students consuming both substances at moderate-to-high levels attained significantly lower GPA at both the outset and across the two-year investigation period. Follow-up analysis showed significant improvement in GPA when students curtailed their substance use compared to those who continued moderate or high levels of marijuana and alcohol over the two year period.

Why Does This Matter?

Today 8,000 more Americans, mostly children and adolescents under age 18, will use an illicit drug for the first time. Substance use, misuse and dependence have considerable effects on development and also academic performance, beyond GPA.

Each Year…

  • More than 1,700 students die from alcohol poisoning and alcohol-related injuries.
  • 700,000 students are assaulted by classmates who were drinking.
  • Almost 100,000 students are victims of alcohol-related sexual assaults and rapes.

As drug and alcohol abuse increase among our young people, we can expect a further decline in school performance and an increase in referral to addiction and psychiatric treatment.

Prevention, plus better and more accessible treatment is absolutely necessary if we are to reverse this disturbing trend.