Drinking Motives Underlying Internalizing and Externalizing Pathways to Alcohol Misuse in College Students

Alcohol misuse is widespread among college students and is believed to have a heterogeneous genetic and environmental etiology. Different types of drinking motives, such as drinking to cope with stress versus drinking to... [ view full abstract ]

Alcohol misuse is widespread among college students and is believed to have a heterogeneous genetic and environmental etiology. Different types of drinking motives, such as drinking to cope with stress versus drinking to enhance positive feelings, provide a theoretical mechanism behind distinct “internalizing” and “externalizing” pathways to alcohol misuse. Drinking motives are heritable and are robust proximal predictors of alcohol misuse; however, little is known about the nature of these relationships, and whether they are due to a shared liability or direct etiological mechanisms. The nature of the relationships between drinking motives and internalizing/externalizing psychopathology is also uncertain. Our aim is therefore to test different models of the relationships between these outcomes using a genetically informative longitudinal sample of college students (“Spit for Science”, N=9,889) who completed self-report surveys with measures of drinking motives, alcohol use disorder symptoms (AUDsx), and internalizing and externalizing (INT/EXT) psychopathology. Cross-lagged panel analyses were used to test direct phenotypic relationships between these outcomes across the college years. Genome-wide complex trait analysis (GCTA) and LD score regression (LDsc) were used to test for a shared genetic etiology. Cross-lagged model results indicated a stronger directional association from drinking motives to AUDsx than vice versa, indicative of a direct mechanism by which drinking motives shape alcohol misuse. Shared liability, or reciprocal causation, appeared to drive the associations between INT/EXT and drinking motives. Preliminary results from GCTA/LDsc suggest genetic overlap across types of motives, but not between motives and INT. The findings help to clarify the nature of the relationships between drinking motives, alcohol misuse, and internalizing and externalizing psychopathology, and indicate a mechanism by which drinking motives directly influence alcohol misuse. Future analyses will further investigate shared genetic etiologies to provide insight into the role that drinking motives play in internalizing and externalizing pathways to alcohol misuse.