The effect of internal possession laws on underage drinking among high school students: a 12-state analysis.

Objectives: We assessed the effect of internal possession (IP) laws, which allow law enforcement to charge underage drinkers with alcohol possession if they have ingested alcohol, on underage drinking behaviors.

Methods: We examined Youth Risk Behavior Survey (YRBS) data from 12 states with IP laws and with YRBS data before and after each law's implementation. We used logistic regression models with fixed effects for state to assess the effects of IP laws on drinking and binge drinking among high school students.

Results: Implementation of IP laws is associated with reductions in the odds of past-month drinking. This reduction was bigger among male than among female adolescents (27% vs 15%) and only significant among younger students aged 14 and 15 years (15% and 11%, respectively). Male adolescents also reported a significant reduction (24%) in the odds of past-month binge drinking under IP laws.

Conclusions: These findings suggest that IP laws are effective in reducing underage drinking, particularly among younger adolescents.