Associations Between Solitary Drinking and Increased Alcohol Consumption, Alcohol Problems, and Drinking to Cope Motives in Adolescents and Young Adults: a Systematic Review and Meta-analysis

Background And Aims: Emerging evidence suggests that solitary drinking may be an important early risk marker for alcohol use disorder. The current paper is the first meta-analysis and systematic review on adolescent and young adult solitary drinking to examine associations between solitary drinking and increased alcohol consumption, alcohol problems, and drinking to cope motives.

Methods: PsychINFO, PubMed, and Google Scholar were searched using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology and a pre-registered International Prospective Register of Systematic Reviews (PROSPERO) protocol (no. CRD42020143449). Data from self-report questionnaires regarding negative correlates of solitary drinking (e.g. alcohol problems) and solitary drinking motives (e.g. drinking to cope) were pooled across studies using random-effects models. Studies included adolescents (aged 12-18 years) and young adults (mean age between 18 and 30 years or samples with the majority of participants aged 30 years or younger).

Results: Meta-analytical results from 21 unique samples including 28,372 participants showed significant effects for the associations between solitary drinking and the following factors: increased alcohol consumption, r = 0.23, 95% confidence interval (CI) = 0.12, 0.33; drinking problems, r = 0.23, 95% CI = 0.13, 0.32; negative affect, r = 0.21, 95% CI = 0.16, 0.26; social discomfort, r = 0.17, 95% CI = 0.06, 0.27; negative reinforcement, r = 0.28, 95% CI = 0.24, 0.31; and positive reinforcement, r = 0.10, 95% CI = 0.03, 0.17. These associations were not moderated by age group (i.e. adolescent versus young adult), study quality, or differing solitary drinking definitions. Accounting for publication bias increased the effect sizes from r = 0.23 to 0.34 for alcohol consumption and from r = 0.23 to 0.30 for drinking problems, and lowered it from r = 0.10 to 0.06 and r = 0.17 to 0.11 for positive reinforcement and social discomfort, respectively.

Conclusions: Solitary drinking among adolescents and young adults appears to be associated with psychosocial/alcohol problems and drinking to cope motives.