The Relationship Between Childhood Trauma and Substance Use Disorders: A Systematic Review
This systematic review aimed to synthesize primary evidence on the relationship between childhood trauma and adverse childhood experiences and alcohol or other psychoactive substance use or related disorders during adolescence or adulthood. Methods: Google Scholar, DergiPark, and TR Dizin were searched using Turkish and English keywords between January 2026 and August 17, 2026. In accordance with PRISMA 2020, 18 of the 96 identified records were removed as duplicates, 78 records were screened, 58 full-text reports were assessed, and 14 reports were excluded with reasons provided. Forty-four eligible primary observational studies were examined through structured narrative synthesis without meta-analysis. Study-level methodological quality was assessed using design-appropriate JBI checklists, while the certainty of evidence across outcome groups was evaluated using the GRADE approach. Results: Most studies reported positive associations between childhood trauma and earlier substance use initiation, frequency of use, alcohol or substance use disorders, overdose, and clinical severity. A cumulative exposure and dose–response pattern recurred across diverse samples. However, some associations weakened after adjustment for genetic and familial factors and other adverse childhood experiences; in certain clinical and child protection samples, no significant differences were found in consumption amount or by maltreatment type. GRADE rated evidence on alcohol, general substance use disorder, and initiation outcomes as low certainty and evidence on cannabis and clinical severity outcomes as very low certainty. Moreover, the absence of eligible primary studies from Türkiye highlighted a local evidence gap and the need for context-specific research. Conclusion: Childhood trauma is an important risk marker; however, heterogeneous measures, retrospective self-reports, confounding factors, and observational designs limit causal interpretation. The findings support safe, voluntary, trauma-informed assessment in addiction services and prospective, multicenter, well-controlled research.