Marijuana commercialization and adolescent substance treatment outcomes in Colorado.

BACKGROUND AND OBJECTIVES: In Colorado, marijuana was legalized for medical use in 2000, commercialized in 2009, and approved for recreational purposes in 2012. Little is known about the association between recent policy changes and adolescent substance treatment outcomes measured by urine drug screens (UDS). This study addressed this research gap.

METHODS: Participants were youth (N = 523) aged 11-19 years who were enrolled in an outpatient motivational interviewing (MI)/cognitive behavioral therapy (CBT) plus contingency management (CM) in Denver, Colorado from October 2007 to June 2014. The measures included UDS collected during weekly treatment sessions and sent to a commercial laboratory for quantitative analysis of tetrahydrocannabinol (THC)/Creatinine (Cr). Linear regression models and logistic regression models using a Generalized Estimating Equations (GEE) approach for repeated measures were completed to answer the study aims.

RESULTS: Males, but not females, had a marginally significant increasing trend over time in monthly average THC/Cr (β = 1.99, p = 0.046). There was a significant increasing trend over time (per 30 days) in the odds of having a negative UDS within 6 sessions (OR = 1.02, 95%CI = 1.003-1.04, p = 0.006).

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE: Based on these data, substance treatment outcomes from MI and CBT are mixed, but overall treatment appears to remain effective in a state with legalized marijuana. (Am J Addict 2017;26:802-806).