An evaluation of the full level of response to alcohol model of heavy drinking and problems in COGA offspring

Objective: The low level of response (LR) to alcohol is an endophenotype related to heavier drinking and alcohol problems. Structural equation models (SEMs) indicate LR affects alcohol outcomes (ALCOUT) both directly and through mediation by drinking in peers (PEER), alcohol expectancies (EXPECT), and drinking to cope with stress (COPE), with some variation depending on the sample tested. This article presents the fi rst full test of this LR-based model in young subjects from the Collaborative Study on the Genetics of Alcoholism (COGA). Method: Data were generated from 325 12- to 22-year-old 47.4% male) drinking offspring from COGA families, using the Self-Report of the Effects of Alcohol questionnaire to determine LR early in the drinking career and a validated, structured interview for demography and alcohol use/problem patterns. Standardized questionnaires were used to measure PEER, EXPECT, and COPE, with the model tested through the maximum likelihood estimation for analyses of the variance/covariance matrix using both Amos and Mplus. Results: The SEM yielded good fit characteristics and explained 59% of the variance, with LR relating both directly to ALCOUT and as partially mediated by PEER and COPE. Although GENDER related to both LR and ALCOUT in the model, and AGE related to ALCOUT, the SEM results were invariant across both AGE and GENDER, with generally similar invariant results regarding the presence or absence of an alcohol-use disorder diagnosis. Conclusions: The results support the applicability of the LR-based model of heavy drinking and alcohol problems in the COGA offspring, a group with different demography compared with the two other samples of adolescents tested to date. The modest differences observed across samples will be evaluated in future research to enhance understanding of how the model operates across socioeconomic groups.