Multi-substance interventions addressing tobacco and/or cannabis to reduce use

Multi-substance interventions targeting both tobacco and cannabis were found in a systematic review with Bayesian meta-analysis (Walsh et al., 2020, 11 RCTs, N = 1117) to have a significant effect on:

• cannabis cessation, (RR=1.48 [0.92,2.49], studies=8) and no clear effect on tobacco cessation (RR=1.10 [0.68,1.87], studies=9)
• Subgroup analysis suggested multi-substance interventions might be more effective than cannabis targeted interventions on cannabis cessation (RR= 2.19 [1.10, 4.36] versus RR=1.39 [0.75,2.74]).

Interventions eamined consisted of nicotine replacement therapies alongside a behavioural component for tobacco and of mainly behavioural interventions for cannabis