Dimensional and categorical phenotypes using tobacco use disorder criteria: Investigating socio-demographic, psychiatric and clinical correlates

Abstract

Aims: Colorado (CO) passed laws approving medical marijuana in 2000 and legal recreation use of marijuana in 2012. Using data from individuals 18 and older from the Addiction Severity Index Multimedia Version (ASI-MV) post-marketing surveillance system, we assessed trends in initiation and prevalence of marijuana use in CO from 2008 to 2014. Methods: Data included unique responses from 13,945 clients being assessed with the ASI-MV for treatment need in 35 CO substance abuse treatment centers from January 1, 2008 to September 30, 2014. Descriptive statistics and generalized estimating equation models explored trends over time in past year initiation and prevalence of marijuana use, controlling for age, gender, race, and 3-digit ZIP code. We also tested for associations with nonmedical prescription opioid use (NMPU). Results: 48% of respondents were under 34, 40% were female, 51%were non-Whiteminority, and the primary substance of abuse was 45.2% alcohol, 14.7% marijuana, 11.5% cocaine, 7.1% prescription opioids, and 6.8% heroin. There was no statistically significant increase in initiation of marijuana use over the study period. Initiation was 12.2% (95% CI: 3.4%, 35.6%) in Q12008 and 17.8% (95% CI: 13.4%, 23.4%) in Q32014. Initiationwas associated (all p< .0005) with younger age (adjusted odds ratio (aOR) 3.53 for <21; 1.63 for age 21–34), Black race (aOR 1.66) and NMPU (aOR 1.5). There was a statistically significant increase (p< .0001) in prevalence of marijuana use over the study period. Prevalence was 21.3% (95% CI: 12.0%, 34.8%) inQ12008and32.8% (95%CI: 28.5%, 37.5%) inQ32014. Prevalent use was associated (all p< .0005) with younger age (aOR 3.11 for <21; 1.63 for age 21–34; 0.67 for age 55+), NMPU (aOR 2.15), and use of prescription opioids as prescribed (aOR 1.50). Conclusions: Among people being assessed for substance use treatment need, prevalence but not initiation of marijuana use increased over time in Colorado, despite more permissive marijuana use laws. Findings suggest importantmotivations for use and highlight health disparities. Financial support: Supported by Inflexxion, Inc.