Citation

Fink DS, Stohl M, Sarvet AL, Cerdá M, Keyes KM, Hasin DS. Addiction 2020; ePub(ePub): ePub.

Affiliation

Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, NY, USA.

Copyright

(Copyright © 2020, John Wiley and Sons)

DOI

10.1111/add.15031

PMID

32141142

Abstract

BACKGROUND AND AIMS: Medical marijuana law (MML) enactment in the US has been associated with increased cannabis use but lower traffic fatality rates. We assessed the possible association of MML and individual-level driving under the influence of cannabis (DUIC), and also under the influence of alcohol (DUIA). DESIGN AND SETTING: Three cross-sectional U.S. adult surveys: The National Longitudinal Alcohol Epidemiologic Survey (NLAES; 1991-1992), the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC; 2001-2002), and the NESARC-III (2012-2013). PARTICIPANTS: The total n was 118,497: 41,764, 41,184 and 35,549 from NLAES, NESARC, and NESARC-III. MEASUREMENTS: Across the three surveys, similar questions in the Alcohol Use Disorder and Associated Disabilities Interview Schedule assessed DUIC and DUIA. Ever-MML states enacted MML between 1991-1992 and 2012-2013 (overall period). Early-MML states enacted MML between 1991-1992 and 2001-2002 (early period). Late-MML states enacted MML between 2001-2002 and 2012-2013 (late period). MML effects on change in DUIC and DUIA prevalence were estimated using a difference-in-differences specification to compare changes in MML and other states.

FINDINGS: From 1991-1992 to 2012-2013, DUIC prevalence nearly doubled (from 1.02% to 1.92%), increasing more in states that enacted MML than other states (difference-in-differences [DiD]=0.59%; 95%CI=0.06%-1.12%). Most change in DUIC prevalence occurred between 2001-2002 and 2012-2013. DUIC prevalence increased more in states that enacted MML 2001-2002 to 2012-2013 than in never-MML states (DiD=0.77%; 95%CI= -0.05%-1.59%), and in two early-MML states, California (DiD=0.82; 95%CI=0.06-1.59) and Colorado (DiD=1.32; 95%CI=0.11-2.53). In contrast, DUIA prevalence appeared unrelated to MML enactment.

CONCLUSIONS: Medical marijuana law enactment in US states appears to have been associated with increased prevalence of driving under the influence of cannabis, but not alcohol.

Keywords: Cannabis impaired driving, Ethanol impaired driving

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Language: en

Keywords

Drug policy; driving under the influence; marijuana law; medical cannabis