Alcohol Pretreatment Did Not Produce a Dose-Dependent Increase in Cannabis Self-Administration

In a laboratory study summarized in a co-use review, increasing the alcohol pretreatment dose did not produce a dose-dependent change in subsequent cannabis self-administration. That result concerns motivation and consumption under the tested conditions, not the safety of combining the drugs.

Participants could choose their cannabis intake

Yurasek and colleagues’ 2017 review describes alcohol and cannabis users receiving placebo or one of two alcohol doses before a 60-minute session in which cannabis smoking was available ad libitum. Alcohol preceded the smoking session by 30 minutes.

Unlike an experiment assigning a fixed cannabis exposure, this design allowed self-administration. It therefore addressed how alcohol pretreatment influenced subsequent cannabis-taking behavior within the session.

The null result has a defined scope

The review reports that cannabis self-administration was not dose-dependently affected by the alcohol pretreatments. This does not establish exact equivalence under every condition, nor does it rule out differences at other doses, with other products or over longer periods.

It also does not answer the reverse question: how cannabis use affects subsequent alcohol consumption. Treatment order is part of the experiment, and reversing it would test a different sequence.

Consumption and impairment remain different outcomes

A person could consume a similar amount of cannabis after alcohol while experiencing a different combined drug effect. The absence of a dose-dependent self-administration result cannot be used as evidence of unimpaired performance.

The review discusses consumption, pharmacokinetics and behavioral performance in separate sections for good reason. This study contributes a bounded result about subsequent cannabis use. It does not cancel evidence about the effects of co-administration or establish a safe alcohol–cannabis combination.

Related reading: Concurrent Alcohol–Cannabis Use Did Not Necessarily Mean Same-Occasion Use.

Research cited

Yurasek AM, Aston ER and Metrik J. Co-use of Alcohol and Cannabis: A Review (2017). This analysis draws on the review’s discussion of the cited experiments.