Trends in Substance Use and Perceived Availability of Drugs in Washington State Among Adolescents: Differences By Race/Ethnicity

Introduction. We are in a period of significant secular change regarding marijuana policy, and there is concern that loosening restrictions will result in increased use by adolescents. Washington State is one of few states with retail marijuana, and is therefore an ideal setting to examine trends in adolescent use. In this presentation, we will examine trends in substance use (marijuana, alcohol, and tobacco) among adolescents. We specifically explore differences by race/ethnicity.

Methods. Data for this study came from the Healthy Youth Survey administered biennially to a statewide representative sample of 10^th and 12^th graders in Washington State spanning 2004-2014. The outcomes of this study were: (1) current marijuana, alcohol, and cigarette use (operationalized as any use, used 6+ times, and used 10+ times in the past 30 days), and (2) perceived availability of these drugs at each assessment year. Trends over time in substance use and perceived availability of the substances were examined in a series of logistic regression models for the overall sample as well as in models that were stratified by eight race/ethnicity groups: Black, White, Latino, American Indian/Alaskan Native, Asian, Native Hawaiian/Pacific Islander, Multi-Racial and Other. The models controlled for sex and age of participants, and adjusted standard errors for clustering of students within schools.

Results. There was a significant increase in the perceived availability of marijuana, and decreases in the perceived availability of alcohol and cigarettes over the study period. Although marijuana use increased over the time period, alcohol and cigarette use decreased among participants. There were, however, differences in these trends for substance use and perceived availability of drugs by race/ethnicity. Latino youth had greatest increase in the prevalence of any past 30-day marijuana use, while American Indian youth’s prevalence of any past 30-day marijuana use remained relatively stable. American Indian youth had the largest decreases in the prevalence of frequent drinking (i.e., 10+ times in the past 30 days). Follow-up analyses will examine whether changes in perceived availability of drugs explains the changes in the prevalence of substance use for the different groups.

Conclusions. Increases in the use and perceived availability of marijuana, coupled with decreases in the use and perceived availability of alcohol and cigarettes, suggest that retail marijuana may be negatively impacting Washington youth.  Latino youth had particularly large increases in marijuana use, highlighting the need for further investigation among this population.