Do Youths Substitute Alcohol and Marijuana? Some Econometric Evidence

Data from the 1982 and 1989 Monitoring the Future Surveys are used to examine the substitutability of alcoholic beverages and marijuana among youths. Beer prices and minimum legal drinking ages are used as measures of the full price of alcohol, while an indicator of marijuana decriminalization and its money price capture the full price of marijuana. Results indicate that drinking frequency and heavy drinking episodes are negatively related to beer prices, but positively related to the full price of marijuana. The implications of this substitution for one of the consequences of youth substance abuse, driving while intoxicated, is examined using information on youth non-fatal accidents taken from the surveys and on youth fatal motor vehicle accidents constructed from the Fatal Accident Reporting System. These results indicate that the net effect of an increase in the full price of alcoholic beverages on the probability of a youth traffic crash is negative. However, the opposite is found for marijuana. That is, the results imply that the reduction in accidents resulting from substitution away from alcoholic beverages and other intoxicating substances to marijuana as its full price is lower more than offsets the increase in accidents related to marijuana use.