A longitudinal study of adolescent psychotic experiences and later development of substance use disorder and suicidal behavior

Abstract

Introduction: Psychotic experiences are associated with later substance use disorder and suicidal behavior, but individual psychotic experiences have not been examined in a longitudinal data set. Also, the potential dose-response relationship between these phenomena remains unknown.

Method: Cohort study including 9242 adolescents who participated in The Child and Adolescent Twin Study in Sweden (CATSS). At ages 15 and/or 18, seven psychotic experiences (auditory and visual hallucinations, and five delusions) were assessed via questionnaires. Outcomes at follow-up were physician-assigned diagnoses of substance use disorder and suicide attempts ascertained from the Swedish Patient Register. Associations were estimated with Cox regressions and expressed as hazard ratios.

Results: All psychotic experiences were associated with later substance use disorder and/or suicide attempts, with hazard ratios ranging from 1.6 to 3.0. A dose-response relationship was observed between psychotic experiences and later substance use disorder, and suicide attempt.

Discussion: Auditory and visual hallucinations as well as delusions in adolescence are associated with later development of substance use disorder and suicide attempt, and there is a dose-response relationship between the load of psychotic experiences and these adverse outcomes. Clinicians should assess subclinical hallucinations as well as delusions in psychiatric evaluations of adolescents.

Keywords: Epidemiology; Psychotic experiences; Substance use disorder; Suicide attempt.