Mortality among adolescent and young adults in specialized substance use treatment: a Swedish register study

Individuals with substance use problems have higher mortality risks than the general population. This study aimed to assess all-cause and specific-cause mortality among adolescents and young adults in specialized substance use treatment in Sweden, a largely overlooked group in the literature.

A registry cohort was compiled of patients (13-25 years) who between 2011 and 2021 were in contact with Sweden's largest healthcare provider of adolescent substance use treatment, with mortality data covering the same period. Sex, migrant background, parental education, convictions and treatment variables were compiled from registries and included as predictors. We calculated crude mortality rates (CMRs) and estimated Cox regression models to explore the associations between the predictors and mortality. This also included testing for interactions between convictions and treatment variables.

Among 23,709 patients, 229 deaths were recorded, meaning that slightly less than 1% died during the follow-up window. The overall CMR was 1.68 deaths per 1000 person years (95% CI = 1.47-1.91), with differences across some predictors. In the fully adjusted Cox regression, significantly elevated mortality risks were observed among males (HR = 1.69, 95%CI = 1.23-2.32), those who had received inpatient treatment (HR = 1.89, 95% CI = 1.42-2.52), and those who had been convicted (HR = 2.64, 95%CI = 1.92-3.63). No significant difference in mortality risk was observed for migrant status, parental education, or number of outpatient visits in the fully adjusted models. Among convicted patients, more outpatient visits were related to a lower mortality risk (HR = 0.98, 95%CI = 0.98-0.99), whereas inpatient treatment was associated with a higher mortality risk (HR = 2.14, 95%CI = 1.13-4.05).

Almost one out of hundred patients died during the follow-up period, greatly exceeding the mortality rate in adolescents and young adults in the general Swedish population. The mortality risk varied according to sex, treatment experiences, and convictions, but not according to migrant background or parental education. In sum, we report a complex relation between convictions, treatment, and excess mortality among adolescents and young adults enrolled in specialized substance use treatment, signaling profound unmet clinical and social work needs.