The co‐occurring use and misuse of cannabis and tobacco: a review

Abstract

Aims Cannabis and tobacco use and misuse frequently co-occur. This review examines the epidemiological evidence supporting the lifetime co-occurrence of cannabis and tobacco use and outlines the mechanisms that link these drugs to each other. Mechanisms include (a) shared genetic factors; (b) shared environmental influences, including (c) route of administration (via smoking), (d) co-administration and (e) models of co-use. We also discuss respiratory harms associated with co-use of cannabis and tobacco, overlapping withdrawal syndromes and outline treatment implications for cooccurring use. Methods Selective review of published studies. Results Both cannabis and tobacco use and misuse are influenced by genetic factors and a proportion of these genetic factors influence both cannabis and tobacco use and misuse. Environmental factors such as availability play an important role, with economic models suggesting a complementary relationship where increases in price of one drug decrease the use of the other. Route of administration and smoking cues may contribute to their sustained use. Similar withdrawal syndromes, with many symptoms in common, may have important treatment implications. Emerging evidence suggests that dual abstinence may predict better cessation outcomes, yet empirically researched treatments tailored for co-occurring use are lacking. Conclusion There is accumulating evidence that some mechanisms linking cannabis and tobacco use are distinct from those contributing to co-occurring use of drugs in general. There is an urgent need for research to identify the underlying mechanisms and harness their potential etiological implications to tailor treatment options for this serious public health challenge.

Substance use, medication adherence and outcome one year following a first episode of psychosis

“…Finally, cannabis and tobacco are often consumed together in the same joint and there is accumulating evidence of a common underlying biological vulnerability to both substances (Agrawal et al, 2012). Even if this study aims statistically to assess the independent effect of each substance on both medication adherence and remission, further research is needed to definitively disentangle their independent contribution on patients' clinical outcome.…”

Feasibility of a group cessation program for co-smokers of cannabis and tobacco

“…Moreover, a laboratory study of non-treatment-seeking marijuana users revealed that co-smokers of cigarettes were more likely to relapse after a phase of cannabis abstinence compared with non-cigarette smokers [17]. Smoking cigarettes is assumed to provide behavioural and physiological cues for cannabis smoking and vice versa, which may explain the increased probability of relapsing among co-smokers [7,15]. In line with this hypothesis, a study analysed adolescents in substance-abuse treatment and found that never-smokers and those non-smokers who quit using tobacco during their marijuana treatment had a lower risk of marijuana relapse than those who continued or initiated tobacco smoking during treatment [16].…”

“…While cannabis dependence is usually treated in the psychiatric care system, interventions for tobacco users are part of the general public health system [18,19]. Recently, several reviews and a demand analysis identified a need for interventions tailored to co-smokers of tobacco and cannabis [7,[20][21][22]. To date, one small pilot study evaluated individual cognitive behavioural therapy combined with nicotine replacement therapy (NRT) for co-occurring cannabis and nicotine dependence [23].…”

“…both substances are typically smoked) and co-administration (e.g. tobacco is added to cannabis joints in a process known as "mulling") [7]. In Australia, mulling is a widespread way of delivering cannabis [8][9][10] and in Switzerland 90% of cannabis users smoke joints mixed with tobacco [11].…”

Cannabis Use and Disorder Transitions Among a Mixed Community Sample of At-Risk Adolescents and Adults: A Prospective New Zealand Study

“…For example, prototypical subgroups include: high chronic, decreasers, increasers, experimental users, abstainers, 'fling', rare. Conjoint/comorbid cannabis, alcohol, and tobacco use trajectories are also appearing [14,[24][25][26].…”