Background and aims: Solitary drinking in adolescents and young adults is associated with greater risk for alcohol problems, but it is unclear whether this association exists in older demographics. The current paper is the first meta-analysis and systematic review, to our knowledge, to determine whether adult solitary drinking is associated with greater risk for alcohol problems.
Methods: PsychINFO, PubMed and Google Scholar were searched following a pre-registered International Prospective Register of Systematic Reviews (PROSPERO) protocol (CRD42019147075) and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology. Following the methodology used in our recent systematic review and meta-analysis on adolescent/young adult solitary drinking, we systematically reviewed solitary drinking measures/definitions, prevalence rates and associated demographic variables in adults. We then meta-analyzed (using random-effects models) associations between adult solitary drinking and alcohol use/problems, negative affect and negative/positive reinforcement-related variables (e.g. drinking to cope or for enhancement).
Results: Solitary drinking was defined as drinking while physically alone in nearly all studies, but measures varied. Prevalence rates were generally in the 30-40% range, with some exceptions. In general, males were more likely than females to report drinking alone, and married individuals were less likely than unmarried individuals to report drinking alone; racial/ethnic differences were mixed. Meta-analytical results showed significant effects for the associations between solitary drinking and the following factors: alcohol consumption, r = 0.25, 95% confidence interval (CI) = 0.18, 0.33, k = 15, I2 = 97.41; drinking problems, r = 0.15, 95% CI = 0.10, 0.21, k = 14, I2 = 92.70; and negative reinforcement, r = 0.24, 95% CI = 0.14, 0.32, k = 11, I2 = 89.77; but not positive reinforcement, r = 0.02, 95% CI = 0.06, 0.09, k = 8, I2 = 76.18; or negative affect, r = 0.03, 95% CI = -0.02, 0.08, k = 8, I2 = 52.06. Study quality moderated the association between solitary drinking and negative affect (β = -0.07, P < 0.01) such that lower-quality studies were significantly associated with larger effect sizes. Study quality was generally low; the majority of studies were cross-sectional.
Conclusions: Solitary drinking appears to have a small positive association with alcohol problems.
Keywords: Adults; alcohol use disorder; drinking alone; drinking to cope; meta-analysis; mid-life adults; older adults; solitary drinking; systematic review.
© 2020 Society for the Study of Addiction.