Purpose <p>Investigating the relationship between self-reported mental health and secondary care utilisation can provide evidence on the link between population-level common mental conditions and clinical care; however, cohort studies with linked administrative data are rare. We explored the link between self-reported mental health in adolescence and mental health-related hospital attendance in young adulthood.</p> Methods <p>Data from a nationally representative English cohort (Next Steps) were linked to NHS Hospital Episode Statistics. GHQ-12 assessed psychological distress in Next Steps at age 15; participants were followed up until their first mental health-related hospital presentations and outpatient treatments or were censored at the end of the study (age 27). Cox proportionate hazard models with survey weights estimated associations.</p> Results <p>Out of 4058 young people, 19% reported high levels of distress at age 15. During the 12-year follow-up, 5.3%, 2.9% and 2.7% of the participants had at least one mental disorder, drug/alcohol misuse and self-harm presentation, respectively, and 4.2% had a mental health treatment in NHS hospitals. Higher GHQ-12 scores were associated with mental disorder presentations (HR = 1.10, 95% CI:1.04–1.16), and mental health treatments (HR = 1.14, 95% CI:1.08–1.20). Associations for hospital treatments were weaker for young people living in deprived areas, or if their main parent had lower education.</p> Conclusion <p>Adolescent psychological distress is associated with subsequent hospital attendance in young adulthood, but there might be treatment gaps in service utilisation among more disadvantaged individuals. Detecting youth with mental health difficulties may facilitate early intervention, improve life-course outcomes, and ultimately reduce secondary healthcare use.</p>