Treatment Implications Associated with Cannabis and Tobacco Co-Use.

PURPOSE OF THE REVIEW: The goal of this article is to summarize the treatment-focused literature on cannabis and tobacco co-use and the treatment implications of co-use. This review will focus on: 1) the impact of co-use on cessation outcomes, 2) compensatory use/substitution of the non-treated substance among co-users, and 3) treatment interventions to address co-use. This article will highlight the limitations to co-use captured in the literature and offer considerations and directives for co-use research and treatment moving forward. RECENT FINDINGS: The degree to which co-use affects cessation for a single, targeted substance remains in question, as the literature is largely mixed. Cannabis treatment trials are better equipped to answer these questions given that they do not typically exclude tobacco users. While the relationship between tobacco use and poorer cannabis outcomes appears to have some evidence, the reverse relationship (cannabis use affecting tobacco outcomes) is not consistently supported. SUMMARY: The co-use of cannabis and tobacco and its impact on single substance cessation and/or compensatory substance use during cessation is generally overlooked in treatment trials, while interventions to address both substances are rare. Capturing co-use adds burden for researchers, clinicians, and participants, but is warranted given the prevalence of co-use and a rapidly changing cannabis and tobacco regulatory environment, which may further complicate co-occurring substance use. Co-users are a heterogeneous population; trials focused on co-users, in addition to better data capture and consistent terminology, will aid in an understanding of nuanced patterns of co-use critical to inform treatment interventions.

Does cannabis use moderate smoking cessation outcomes in treatment-seeking tobacco smokers? Analysis from a large multi-center trial.

BACKGROUND AND OBJECTIVE: Tobacco and cannabis are frequently used in combination and cannabis co-use may lead to poor tobacco cessation outcomes. Therefore, it is important to explore if cannabis co-use is associated with a reduced likelihood of achieving successful tobacco abstinence among treatment-seeking tobacco smokers. The present study examined whether current cannabis use moderated tobacco cessation outcomes after 12 weeks of pharmacological treatment (varenicline vs. nicotine patch vs. placebo) with adjunctive behavioral counseling. METHODS: Treatment-seeking tobacco smokers (N = 1,246) were enrolled in an intent-to-treat study, of which 220 were current cannabis users. Individuals were randomly assigned to 12 weeks of placebo (placebo pill plus placebo patch), nicotine patch (active patch plus placebo pill), or varenicline (active pill plus placebo patch), plus behavioral counseling. The primary endpoint was biochemically verified 7-day point prevalence abstinence at the end of treatment. RESULTS: Controlling for rate of nicotine metabolism, treatment arm, age, sex, alcohol, and level of nicotine dependence, cannabis users were as successful at achieving biochemically verified 7-day point prevalence abstinence compared to tobacco-only smokers. CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE: Findings suggest that cannabis use does not hinder the ability to quit tobacco smoking. Future tobacco cessation studies should employ prospective, longitudinal designs investigating cannabis co-use over time and at different severity levels. (Am J Addict 2016;25:291-296).

Correlation of prepulse inhibition and Wisconsin Card Sorting Test in schizophrenia and controls: effects of smoking status.

BACKGROUND: In schizophrenia, neurocognitive deficits associated with the illness are modulated by tobacco smoking. However, little is known about how smoking status modulates the relationships between neurocognitive measures in schizophrenia and healthy control subjects. OBJECTIVE: The goal of this study was to evaluate the relationship between sensorimotor gating assessed by prepulse inhibition (PPI) and executive cognitive function using the Wisconsin Card Sorting Test (WCST) in schizophrenia and controls as a function of smoking status. METHOD: We studied PPI and neuropsychological function in four groups (N=50); smokers with schizophrenia (SS; n=15), control smokers (CS; n=13), non-smokers with schizophrenia (SNS; n=11) and control non-smokers (CNS; n=11). RESULTS: SNS demonstrated the poorest PPI, while SS showed comparably high levels of PPI to CNS. Non-psychiatric controls outperformed patients on WCST outcomes irrespective of smoking status. Several prefrontal outcome measures on the WCST (categories completed, percentage perseverative and non-perseverative errors) correlated significantly with PPI at the 60 and 120 ms prepulse intervals. In contrast, there were no significant correlations between PPI and any WCST outcomes in SNS, CS or CNS, and few significant correlations between PPI and other neuropsychological measures. DISCUSSION: Our preliminary data suggests that the correlation between sensorimotor gating (PPI) and prefrontal executive cognitive functioning (WCST) is enhanced by acute cigarette smoking in schizophrenia.