Substance use disorders (SUDs) are the leading cause of premature death and disability in the Americas, causing approximately 47% of deaths in the world's adult population, posing an enormous public health challenge. One of these challenges is the treatment drop-out, which significantly compromises the efficacy of SUD interventions. Despite the implementation of advanced monitoring programs in Chile, evidence concerning the medium- and long-term effects of SUD treatment remains limited. This study explores the correlation between living arrangements (alone, with the family of origin, or with a partner with or without children [partner/children]) at the onset of initial treatment and the time until treatment drop-out among emerging adults (18–29 years) in public SUD programs in Chile from 2010 to 2019. Employing a retrospective cohort design, health records of adult patients aged 18 to 29 who underwent public SUD treatment between 2010 and 2019 in general population programs were analyzed. Using survival analysis and inverse probability-weighted multinomial logistic regression models, the findings reveal consistent patterns: individuals living with family of origin had the highest survival rates and prolonged treatment retention, followed by those living with partner/children, and those living alone had the lowest survival rates (Restricted mean survival times (year) were 0.60, 0.57, and 0.55 to at one year, respectively). The study emphasizes the crucial role of social bonds, particularly familial and relational ties, in influencing treatment outcomes. In conclusion, this study underscores the necessity to consider social support when formulating effective SUD treatment strategies and the potential positive impact of familial and relational bonds, especially during the critical phase of emerging adulthood.