BackgroundSuicide attempts (SA) are a public health concern because of increasing prevalence and clinical implications. Childhood trauma (CT) and emotion dysregulation (ED) have been proposed as predictors of SA, but few data are available in patients with Substance Use Disorder (SUD). ObjectiveOur study aims to investigate the association of sociodemographic/clinical variables, CT typologies, and ED features with SA in SUD patients. Participants and settingSubjects with SUD were screened in an outpatient setting. The final sample consisted of 226 patients, subdivided according to the presence of lifetime SA (SUD, n = 163 vs. SUD-SA, n = 63). MethodsParticipants were compared for sociodemographic and clinical information. CT and ED were assessed through the Childhood Trauma Questionnaire - Short Form (CTQ-SF) and the Difficulties in Emotion Regulation Scale (DERS), respectively. We performed a mediation analysis to test the effect of CT and ED on SA. ResultsPatients with a history of SA (27.9 %) displayed more psychiatric comorbidities (p = 0.002) and hospitalizations (p < 0.001), higher scores at CTQ-SF sexual abuse (p < 0.001) and DERS ‘impulse’ (p = 0.002), ‘goals’, ‘non-acceptance’, ‘strategies’ (p < 0.001) subscales. The relationship between CTQ-SF sexual abuse and SA was significantly mediated by DERS ‘strategies’ (p = 0.04; bootstrapped 95 % LLCI-ULCI = 0.004–0.024). ConclusionsCT and different dimensions of ED were associated with SA in SUD patients. In our sample, the effects of childhood sexual abuse on SA were mediated by limited access to emotion regulation strategies. SUD patients are burdened with higher all-cause mortality, and CT and lifetime SA can worsen clinical outcomes. Clarifying the reciprocal interactions of psychopathological dimensions may help deliver targeted interventions and reduce suicide risk in specific populations.