Trauma History Among Patients Receiving Methadone Maintenance Treatment: Sex Differences, Characteristics, and Outcomes.

Background: Most patients with opioid use disorder have experienced traumatic events; however, sex differences in trauma exposure, its timing, and its association with treatment outcomes remain unclear. Methods: Of the 1194 patients admitted to a methadone maintenance treatment (1993-2025), 923 completed an intake questionnaire assessing traumatic events and their timing relative to substance use (before, during, "always", or "never"). Predictors of long-term retention were examined using Kaplan-Meier analyses and a Cox multivariate model. Results: Of 923 participants, 23.5% were female, and 74.4% reported trauma. Males (35.7%) more often reported trauma during substance use than females (27.6%), whereas females more frequently reported trauma occurring "always" (31.3%) than males (22.2%; p=0.024). Interpersonal trauma category was more prevalent in females (59% vs. 40.2%, p<0.001) with no differences in physical trauma (50.8%) and self-directed harm (38.8%). The age of opioid initiation was comparable between sexes but females were admitted to MMT younger. Substance use at admission was comparable between sexes, as were one-year and long-term retention (mean=9.8 years, 95% CI 9.1-10.6). Long-term retention between trauma timing groups and trauma categories were comparable, also when stratified by sex. Sex-specific differences emerged only when trauma type and timing were considered. Specifically rape history was associated with shorter retention among males but not females. Conclusion: Traumatic experiences differed between sexes but were not associated with long-term retention and did not change the comparable outcomes between sexes. A bigger sample is needed to confirm the findings of shorter retention in male who experienced rape.