Adverse childhood experiences and loneliness: A systematic review and meta-analysis.

Adverse childhood experiences are considered a powerful determinant of emotional health. One indicator of emotional health is loneliness, which refers to a distressing experience that one's social relationships are less in quality and quantity than those desired. This preregistered review aimed to examine the association between adverse childhood experiences (e.g., physical abuse/neglect, emotional abuse/neglect, sexual abuse, parental separation/divorce, family conflict, domestic violence) and loneliness in adulthood. A database search (Embase, Ovid, Cochrane Library, APA PsychINFO, Medline, Pubmed, Scopus) was conducted. After removal of duplicates, 3689 papers were reviewed and 20 met inclusion criteria. When feasible, results were pooled using a random-effects meta-analysis and inverse variance modelling and reported narratively. Meta-analyses revealed a statistically significant association between cumulative adverse childhood experiences and loneliness (r = 0.30, 95% CI [0.22-0.37]; prediction interval = 0.04-0.52) and between specific adversity types and loneliness, namely sexual abuse, physical abuse, physical neglect, emotional abuse, and emotional neglect. Some heterogeneity was observed across studies. Subgroup and sensitivity analyses revealed no differences in age, gender, age group, continent, or measures of adversity/loneliness. This research indicates that adversities in childhood may have some long-term influences on loneliness, both cumulatively and within adversity subtypes.