Changes in cigarette and alcohol use during cannabis abstinence.

OBJECTIVE

Cannabis causes lower mortality and morbidity than alcohol and tobacco so it is clinically important if quitting cannabis is associated with substitution with these substances. This study tests if cannabis is substituted with alcohol and/or tobacco during cannabis abstinence, and factors predicting such substitution.

METHOD

A secondary analysis of a prospective community based study quantified cannabis, alcohol and tobacco use with Timeline Follow-back during a two-week voluntary cannabis abstinence and at one-month follow-up in non-treatment seeking cannabis users (n=45). Cannabis use was verified by urine THC-COOH levels.

RESULTS

Alcohol use increased by 8 standard units (SU; d=0.48)/week and cigarette use by 14 cigarettes/week (d=0.29) during cannabis abstinence. Those using less of each substance at baseline had greater increases during cannabis abstinence (alcohol P<0.0001, tobacco P=0.01). There was a decrease in alcohol (-4.8 SU, d=-0.29) and tobacco (-13 cigarettes/week, d=-0.26) use at follow-up, when most participants (87%, n=39) had resumed cannabis use. Increased cigarette use was predicted by cannabis withdrawal related sleep difficulty (insomnia) (P=0.05), restlessness (P=0.03) and physical symptoms (P=0.02). Neither alcohol nor cigarette use increased significantly in those (13.3%, n=6) who remained abstinent from cannabis through to follow-up.

CONCLUSIONS

Abstaining from cannabis was associated with increases in alcohol and tobacco use that decreased with resumption of cannabis use; however there were no increases in individuals who remained abstinent from cannabis at one-month follow-up. Tobacco use did not increase in those experiencing milder cannabis withdrawal symptoms. Research on substitution in treatment seekers during outpatient cannabis abstinence is needed.