6.3 Psychotic Experiences in Adolescence and Later Risk of Suicidal Behavior and Substance Use in a Swedish Longitudinal Cohort

Abstract

Background: Psychotic experiences are relatively prevalent in the population and occur across the spectrum of mental disorder diagnoses. Recently, psychotic experiences have been highlighted as markers of risk for poor mental health outcomes, including a strong relationship with suicidal behavior and with substance use disorder. There has, however, been no longitudinal research to examine different subtypes of psychotic experiences as predictors of suicidal behavior and of substance use. Methods: Using a genetically sensitive, cohort twin study (the Child and Adolescent Twin Study in Sweden: CATTS), we investigated the longitu-dinal relationship between 7 subtypes of psychotic experiences in a cohort study of 9242 adolescents followed from age 15 years to age 18 years. We assessed for the presence of auditory and visual hallucinations as well as 5 subtypes of delusional beliefs. Using the national Swedish Patient Register, we looked at subsequent physician diagnoses of suicide attempt and sub-stance use disorder by age 18 years, using Cox regression. Results: All 7 subtypes of psychotic experiences predicted later suicide attempts with hazard ratios ranging from 1.6 to 2.5. Three of the 7 psychotic experiences also predicted later substance use disorder (Visual and auditory hallucinations, and persecutory beliefs), with hazard ratios ranging from 2.7 to 3.0. There was a dose-response relationship between the number of psychotic experiences reported and the odds of suicide attempt and substance use disorder. Conclusion: A wide range of psychotic experiences are predictors of later suicidal behavior, whereas a narrower range of psychotic experiences are predictors of later substance use disorder. These risk markers should be carefully assessed in mental health clinics and can inform about risk of future poor outcomes.