Breaking the cycle: Consequences from simultaneous alcohol and cannabis use predict subsequent simultaneous use and drinks consumed at the next simultaneous use event

Background Research suggests that simultaneous alcohol and cannabis use (vs. alcohol‐only) days are associated with increased alcohol‐related consequences. Less is known, however, regarding whether consequences from simultaneous use events predict the subsequent patterns of simultaneous use and drinking behavior at subsequent simultaneous use events. Methods Young adults who reported 2+ days of simultaneous use ( N = 89) completed a 60‐day timeline followback (TLFB) interview, reporting on simultaneous alcohol and cannabis use and positive/negative consequences experienced on drinking days. Multilevel models tested whether positive and negative consequences from a given simultaneous use event, and their interaction, predicted the likelihood of simultaneously using cannabis at the next drinking event and the number of standard drinks consumed during the next simultaneous use event. Results Contrary to hypotheses, negative consequences from a given simultaneous use event predicted a higher likelihood of cannabis use at the next drinking event, whereas positive consequences and the interaction between the two did not. However, in line with hypotheses, negative consequences from a given simultaneous use event predicted lesser drinks consumed at the next simultaneous use event. Furthermore, there was an interaction between positive/negative simultaneous use consequences predicting drinking quantity during the next simultaneous use event, such that negative consequences from a given simultaneous use event predicted lesser drinks consumed at the next simultaneous use event when positive consequences from the given event were lower (but not higher) than average. Conclusions Findings lend valuable information that may aid substance use prevention and intervention efforts seeking to dissuade against habitual cycles of high‐risk simultaneous use. Findings also provide some evidence of a “teachable moment” from simultaneous use consequences.