Combined use of alcohol and cannabis: Introduction to the special issue.

OBJECTIVE Combined use of alcohol and cannabis has increased in recent years among certain age groups, and it is well established that individuals who use both alcohol and cannabis (especially if they use both at the same time) are at increased risk for substance-related harms relative to individuals who use only one substance. Far less attention has been placed on the patterns, predictors, and psychological processes associated with alcohol and cannabis co-use, which may inform prevention and intervention programming. Accordingly, this special issue was assembled to advance our understanding of the characteristics and consequences of combined use of alcohol and cannabis. METHOD In this introductory article, the Guest Editors present the background for this work and provide an overview of the 14 articles that comprise this special issue. RESULTS Studies contained in this special issue capitalize on a variety of methodologies, with a particular focus on investigating typologies of alcohol and cannabis co-use, clarifying motivational and social contexts of co-use, and tracking co-use in daily life via daily diary and ecological momentary assessment designs. Experimental and neuroimaging examinations of co-use are also included. Collectively, the studies generally provide evidence that combined use of alcohol and cannabis is associated with unique characteristics, predictors, consequences, and psychological processes relative to single-substance use. CONCLUSIONS The studies in this special issue provide new insight into combined use of alcohol and cannabis. They also highlight a number of promising avenues for future inquiry as the literature on alcohol and cannabis co-use continues to grow. (PsycInfo Database Record (c) 2021 APA, all rights reserved).