Review of Nicotine and Cannabis Interactions: Reinforcement May Be Enhanced When Used Together | Research

The takeaway

A comprehensive review found that combining nicotine and cannabis, increasingly common among young people, may enhance reinforcing and anxiety-reducing effects while having opposite effects on appetite and cognition, with adolescent co-use being a particular concern.

Read this if you use both cannabis and tobacco and want to understand how they interact pharmacologically.

Co-use of nicotine and cannabis may enhance reinforcing effects, increasing addiction risk for both

What the researchers found

This review examined the pharmacological interactions between nicotine and cannabis, two drugs increasingly used in combination, especially by adolescents and young adults.

Animal studies suggested that the reinforcing effects of both drugs may be enhanced by joint consumption. Anxiety-reducing effects may also be amplified when used together, which could be particularly appealing to adolescent girls.

However, the two drugs have contrasting effects in other domains: cannabis increases appetite while nicotine suppresses it; cannabis impairs cognition while nicotine may enhance certain cognitive functions. The review highlighted the adolescent period as requiring urgent further investigation, with sex differences emerging as an important variable.

Why it matters

Cannabis and tobacco are frequently co-used, often mixed together in joints. Understanding their pharmacological interactions is critical because enhanced reinforcement from combining them could accelerate addiction to both substances, particularly during the vulnerable adolescent period.

The numbers in context

Two of the most widely used drugs of dependence. Increasingly combined, particularly among adolescents. Animal studies suggest enhanced reinforcement and anxiolytic effects from co-use. Opposite effects on appetite and cognition.

How the study worked

Comprehensive narrative review examining nicotine and cannabinoid system interactions. Covered addiction processes, gateway theories, adolescent effects, anxiety, food intake, and cognition. Drew on animal behavioral studies, human observational data, and pharmacological evidence.

What this study cannot tell us

Much evidence from animal studies that may not directly translate to human use patterns. The review identifies concerns about adolescent co-use but notes the area is "in urgent need of further investigation." Sex differences are emerging but not well characterized.

How to read the evidence

Comprehensive narrative review synthesizing animal and human evidence. Identifies important interaction effects but many findings are preliminary.

When this study was published

Published in 2006. Research on nicotine-cannabis co-use has expanded, particularly regarding vaping and the rise of nicotine-cannabis dual use among young people.

The bigger picture

The "gateway" and "reverse gateway" theories of addiction are discussed: tobacco use may lead to cannabis, but cannabis use may also lead to tobacco. The shared pharmacological interactions between nicotinic and cannabinoid systems at the receptor level provide a biological basis for cross-substance vulnerability.

Questions still open

Does combining cannabis and nicotine increase addiction risk for both substances? Do the opposite cognitive effects (cannabis impairing, nicotine enhancing) cancel each other out during co-use?

Common questions

Does mixing cannabis with tobacco make both more addictive?

Animal studies reviewed here suggest that combining nicotine and cannabis may enhance the reinforcing (rewarding) effects of both drugs, potentially increasing addiction risk. This is particularly concerning for adolescents who frequently co-use these substances.

Why do people mix cannabis and tobacco?

The review suggests the combination may enhance anxiety-reducing effects, which could be appealing, especially to young users. Additionally, nicotine may counteract some of cannabis's cognitive-impairing effects. However, the enhanced reinforcement may accelerate dependence on both substances.

Read the original research

Nicotine and cannabinoids: parallels, contrasts and interactions.

Neuroscience and biobehavioral reviews, 30(8), 1161-81

View on PubMed ↗

Citation

Viveros, Maria-Paz; Marco, Eva M; File, Sandra E. (2006). Nicotine and cannabinoids: parallels, contrasts and interactions.. Neuroscience and biobehavioral reviews, 30(8), 1161-81.