A study led by FAS researchers, Jason Goldstick and Justin Heinze, studied how parental support and perceived peer behaviors increase or decrease the risk for marijuana use and if it is different between age and gender.

Peer influences are found to be the most important risk factor for substance use, and parental support is frequently found to protect against substance use as well. The study explores how these influences for substance use change between gender and age.

The researchers drew data from the Flint Adolescent Study, an 18-year longitudinal study of students with a high risk for high school drop-out in Flint, MI. The sample included 728 students and conducted interviews during high school, 4 years after high school, and 4 more years after. They predicted that peer and parental factors (both negative and positive) would be less important with age in protecting against marijuana use.

The results showed that perceived peer behavior were less important as they got older in both genders. While in males, they found that parental support had strongest influence on marijuana use, but matters less with age. In females, these factors had an even lower importance and no difference in age patterns for peer behavior and parental support.

This study provides evidence that perceived peer behaviors may influence the risk of marijuana use more during adolescence for both genders, and that parental support may have the strongest influence for males.