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



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.



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.



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.
Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Sweden. Electronic address: Martin.Cederlof@ki.se.
Martin
M
Cederlöf
Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Sweden.
Ralf
R
Kuja-Halkola
Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Sweden; School of Medical Sciences, Örebro University, Örebro, Sweden.
Henrik
H
Larsson
Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Sweden.
Arvid
A
Sjölander
Division of Speech and Language Pathology, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Sweden.
Per
P
Östberg
Centre for Ethics, Law and Mental Health (CELAM), University of Gothenburg, Sweden; Gillberg Neuropsychiatry Centre, University of Gothenburg, Sweden.
Sebastian
S
Lundström
Department of Psychiatry, Royal College of Surgeons in Ireland, Ireland.
Ian
I
Kelleher
Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Sweden.
Paul
P
Lichtenstein
D000293:Adolescent; D003702:Delusions / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006212:Hallucinations / Q000453:epidemiology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011618:Psychotic Disorders / Q000453:epidemiology / Q000523:psychology; D012042:Registries; D019966:Substance-Related Disorders / Q000453:epidemiology*; D013406:Suicide, Attempted; D013548:Sweden
Epidemiology; Psychotic experiences; Substance use disorder; Suicide attempt