Treating Alcohol Addiction Also Reduces Cannabis and Cigarette Use — Even When That's Not the Goal | Research

The takeaway

Participants in an alcohol use disorder trial spontaneously reduced cigarette and cannabis use without being prompted, and cannabis reduction in early treatment was inversely associated with alcohol consumption.

Addiction medicine clinicians, AUD researchers, and clinicians treating patients with polysubstance use

What the researchers found

Cigarette use declined significantly over 12 weeks (p=.002); cannabis decreased early (p=.006) then rebounded (p=.03); early cannabis reduction was negatively associated with drinks per drinking day, suggesting a compensatory relationship.

Why it matters

The finding that treating one substance problem can ripple across others challenges the single-substance treatment model — and suggests comprehensive substance use screening should be standard in addiction trials.

The numbers in context

102 participants (61M/41F); significant cigarette reduction (p=.002); cannabis decrease early (p=.006) then increase (p=.03); cannabis changes inversely associated with drinks/drinking day (p<.05).

How the study worked

Secondary analysis of a 12-week RCT of ibudilast for AUD (N=102), examining unprompted changes in cigarette and cannabis use and their associations with drinking outcomes.

What this study cannot tell us

Secondary analysis not powered for these outcomes; relatively small sample; co-occurring use patterns make it difficult to isolate individual substance effects; ibudilast effects on other substances unknown.

How to read the evidence

Secondary analysis of a well-designed RCT with appropriate statistical methods, but limited by small sample and post-hoc nature.

When this study was published

Published in 2026, contributing to the growing evidence for comprehensive substance use assessment in addiction treatment.

The bigger picture

The early cannabis reduction followed by rebound could represent a substitution pattern — patients may initially reduce all substances but then return to cannabis as a coping alternative to alcohol.

Questions still open

Is the cannabis rebound a substitution effect? Would targeting all three substances simultaneously improve outcomes? Should AUD trials routinely track cannabis and tobacco use?

Common questions

Does treating alcohol addiction affect other substance use?

Yes — participants in this alcohol treatment trial spontaneously reduced cigarette and cannabis use without being asked to, suggesting treatment effects can extend beyond the targeted substance.

Is cannabis use related to alcohol consumption?

This study found an interesting pattern: early cannabis reduction was associated with lower alcohol consumption, but cannabis use rebounded later in treatment — possibly as a substitute coping mechanism.

Read the original research

Reductions in cigarette and cannabis use during a randomized clinical trial for alcohol use disorder.

Alcohol and alcoholism (Oxford, Oxfordshire), 61(2)

View on PubMed ↗Publisher’s paper ↗

Citation

Belnap, Malia A; McManus, Kaitlin R; Kirsch, Dylan E; Grodin, Erica N; Ray, Lara A. (2026). Reductions in cigarette and cannabis use during a randomized clinical trial for alcohol use disorder.. Alcohol and alcoholism (Oxford, Oxfordshire), 61(2). https://doi.org/10.1093/alcalc/agag006