Diagnostic pathways, healthcare utilization, and mortality in children and young people with early onset substance use disorders: a nationwide registry-based cohort study

Longitudinal, population-based evidence on the clinical profiles and mortality of youth with substance use disorders (SUDs) is limited, despite significant health and social risks. This study aimed to (1) characterize initial SUD diagnoses, demographic and healthcare profiles, and diagnostic trajectories, and (2) estimate all-cause and external-cause mortality relative to the general population. This nationwide cohort study included 22,449 individuals aged 6–24 newly diagnosed with SUD in the Czech Republic, 2015–2019. Sex-specific crude mortality rates (CMRs) and age-standardized mortality ratios (SMRs) were calculated for children (< 18 years) and young adults (18–29 years) to estimate mortality. The most common initial diagnoses were alcohol use disorders (55%), followed by polysubstance use (14%), and cannabis use disorders (11%). The mean age at first diagnosis was 18.7 years, lower for females (17.9) than males (19.1). Females were more often diagnosed with opioid, sedative/hypnotic, and stimulant use disorders, whereas males with cannabis and polysubstance use disorders ( p < 0.001). During follow-up, 137 individuals (0.6%) died. All-cause and external-cause CMRs were 242.1 and 171.4 per 100,000 person-years, both higher in males (1.9- and 2.6-fold). Excess mortality was observed in both age groups, with all-cause SMRs of 9.5 (95% CI 5.6–16.0) for children and 5.7 (4.8–6.8) for young adults; external-cause SMRs were 19.1 (10.8–33.6) and 6.6 (5.3–8.1), respectively. Early-onset SUD in clinical populations shows substantial sex differences and markedly elevated early, premature mortality. These findings underscore the need for early detection and targeted interventions for vulnerable youth.