Unravelling the complexities of alcohol use in the context of loneliness and stress: a systematic review and proposed model.

Alcohol use is frequently linked to emotional distress, yet findings on how loneliness and stress relate to drinking remain inconsistent. This systematic review synthesized evidence from 39 studies published up to December 2025 that examined associations between alcohol use, loneliness/social isolation, and stress/psychological distress in adult, non-clinical populations. Searches were conducted in PubMed, Scopus, and ScienceDirect. Across cross-sectional and longitudinal designs, stress showed the most consistent positive associations with higher alcohol use and alcohol-related problems. In contrast, links between loneliness and alcohol outcomes were heterogeneous: several studies reported positive associations, others found null or inverse relations, and effects were often contingent on context (e.g., pandemic-related stress), gender, or developmental stage. The loneliness-distress association was the most robust finding, suggesting psychological distress may mediate the influence of social disconnection on drinking. Measurement heterogeneity - multiple alcohol metrics and varied loneliness and stress scales - and population differences limited comparability. Integrating these findings, we propose a multifactorial heuristic model in which stress/psychological distress functions as a proximal emotional precursor to alcohol use, while loneliness/social isolation acts as a distal contextual amplifier whose influence is channelled primarily through distress and depends on coping resources, social support, cultural norms, and demographic factors. These conclusions underscore the need for longitudinal, cross-cultural studies using harmonised measures and for prevention and intervention efforts that jointly target emotional regulation and social connection.