Background: Treatment for substance use disorder (SUD), results, in general, in improvements in terms of both drug use and social functioning. However, there are clients who are in need of repeated treatment. The aim of this retrospective study was to identify, for adults in compulsory care for severe SUD, the association between reporting having experienced a risky psychosocial childhood and repeated entries into the Swedish compulsory care system for SUD. Method: Hierarchical logistic regression and mediation analysis methods were used to analyse data from the Swedish National Board of Institutional Care (SiS) database. The sample included 2719 adults assessed at their compulsory care intake. The study examined the association between history of institutional care, family with SUD or psychiatric problem and repeated compulsory care entries as an adult controlling for main drug, age and gender. Results: In the regression model the factor with the strongest association with repeated compulsory care intakes for SUD, was as a child having been in mandated institutional care ( OR = 2.0 (1.60–2.51)). The proportion of the total effect that is mediated through LVU (law (1990:52) the care of young persons (special provisions) act) was 33% for SUD problems in family during childhood, 44% for psychiatric problems in family during childhood, and 38% for having been in foster care. Conclusion: Having been in mandated institutional care as a youth was strongly associated with repeated compulsory care for SUD as an adult. This is concerning since receipt of services as a child is supposed to mediate against the consequences of risky childhood conditions. These adults, as a group, are in need of a well-coordinated and integrated system of extensive aftercare services to reduce the likelihood of re-entry into compulsory care for an SUD.