Does tobacco dependence worsen cannabis withdrawal in people with and without schizophrenia‐spectrum disorders?

Abstract

AbstractBackground and ObjectivesRates of cannabis use disorder (CUD) are higher in people with schizophrenia than in the general population. Irrespective of psychiatric diagnosis, tobacco co‐use is prevalent in those with CUD and leads to poor cannabis cessation outcomes. The cannabis withdrawal syndrome is well‐established and increases cannabis relapse risk. We investigated whether cannabis withdrawal severity differed as a function of high versus no/low tobacco dependence and psychiatric diagnosis in individuals with CUD.MethodMen with CUD (N = 55) were parsed into four groups according to schizophrenia diagnosis and tobacco dependence severity using the Fagerstrom Test for Nicotine Dependence (FTND): men with schizophrenia with high tobacco dependence (SCT+, n = 13; FTND ≥ 5) and no/low tobacco dependence (SCT−, n = 22; FTND ≤ 4), and nonpsychiatric controls with high (CCT+, n = 7; FTND ≥ 5) and no/low (CCT−, n = 13; FTND ≤ 4) tobacco dependence. Participants completed the Marijuana Withdrawal Checklist following 12‐h of cannabis abstinence.ResultsThere was a significant main effect of tobacco dependence on cannabis withdrawal severity (p < .001). Individuals with high tobacco dependence had significantly greater cannabis withdrawal severity (M = 13.85 [6.8]) compared to individuals with no/low tobacco dependence (M = 6.49, [4.9]). Psychiatric diagnosis and the interaction effects were not significant. Lastly, cannabis withdrawal severity positively correlated with FTND (r = .41, p = .002).Conclusion and Scientific SignificanceAmong individuals with CUD and high tobacco dependence, cannabis withdrawal severity was elevated twofold, irrespective of diagnosis, relative to individuals with CUD and no/low tobacco dependence. Findings from this study emphasize the importance of addressing tobacco co‐use when treating CUD.