Background: Non-suicidal self-injury (NSSI) is highly prevalent in adolescents and may be a behavioural marker for emergent mental illnesses.

Aims: We sought to determine whether sporadic or recurrent NSSI up to the age of 14 years predicted increased risk of new onset of psychiatric disorder in the subsequent 3 years, independent of psychiatric symptoms and social risk factors.

Method: 945 14 year olds with no past/present history of mental illness completed a clinical interview and completed a questionnaire about NSSI at the ages of 14 and 17 years.

Results: Recurrent NSSI at baseline predicted total disorders, depression and eating disorders. Sporadic baseline NSSI predicted new onset of anxiety disorders only.

Conclusions: NSSI (especially recurrent NSSI) in the early adolescent years is a behavioural marker of newly emerging mental illnesses. Professionals should treat both recurrent and sporadic NSSI as important risk factors, and prevention strategies could be targeted at this vulnerable group.

Declaration of Interest: None