The Association of Cannabis Use and Cigarette Smoking with Psychological Distress Among Adults in California.

BACKGROUND: In November 2016, California voters passed the Adult Use of Marijuana Act making recreational cannabis sales legal to adults aged 21and older starting January 1st, 2018. This study aims to understand the relationship of cannabis use and cigarette smoking with serious psychological distress (SPD) in California in light of the legalization of recreational cannabis sales.

METHODS: This cross-sectional study included 42,313 adult participants from the 2017 to 2018 California Health Interview Surveys. We used the Kessler-6 (K6) scale to measure psychological distress in the past 30 days. Multiple logistic regression models were used to examine the association between cannabis/cigarette use and SPD.

RESULTS: Cannabis use was positively associated with SPD (AOR = 2.48, 95% CI = 1.57, 3.91), but this association was not significantly different before and after recreational cannabis sales legalization in California (AOR = 0.82, 95% CI = 0.72, 2.05). Cigarette smoking was also positively associated with SPD (AOR = 2.76, 95% CI = 2.05, 3.71). Compared to those who used neither cannabis nor cigarettes, sole cannabis users (AOR = 2.51, 95% CI = 1.75, 3.60), sole cigarette smokers (AOR = 3.23, 95% CI = 2.28, 4.60), and dual users of cannabis and cigarettes (AOR = 5.65, 95% CI = 4.04, 7.89) were more likely to report SPD. Dual users were also more likely to report SPD than sole cannabis users (AOR = 2.25; 95% CI = 1.48, 3.43) and sole cigarette smokers (AOR = 1.75; 95% CI = 1.18, 2.59).

CONCLUSIONS: These findings provide evidence for the need to develop effective cessation intervention strategies targeting individuals with SPD to reduce their cannabis use and dual-use of cannabis and cigarettes.