Cannabis--psychosis pathway independent of other types of psychopathology.
OBJECTIVE
To investigate if associations between cannabis use and psychotic symptoms occur independently, or occur as a consequence of previous-other types of-psychopathology.


METHODS
A 14-year follow-up study of 1580 initially 4- to 16-year-olds who were drawn randomly from the Dutch general population was conducted. At initial assessment, psychopathology was assessed with the Child Behavior Checklist. Across the 14-year follow-up period, cannabis use and psychotic symptoms were assessed with the Composite International Diagnostic Interview (CIDI). Because cannabis use is generally condoned in The Netherlands, false-negative reports of cannabis use may occur less frequently than in countries with stricter drug policies, which supports the value of the present study.


RESULTS
Survival analyses indicated that the association between cannabis use and psychotic symptoms occurred independently of initial CBCL scores.


CONCLUSIONS
The link between cannabis use and psychotic symptoms is specific, and does not depend on the earlier presence of other types of psychopathology. This indicates that research aimed at unraveling mechanisms that are responsible for this specific association is useful. Further, given the fact that cannabis use seemed to be a specific risk factor for future psychotic symptoms, prevention aimed against cannabis use may prohibit the onset of psychotic symptoms in vulnerable individuals.
Ferdinand
Robert F
RF
Department of Child and Adolescent Psychiatry, Erasmus Medical Center Rotterdam/Sophia Children's Hospital, Dr. Molewaterplein 60, 3015 GJ Rotterdam, The Netherlands. r.f.ferdinand@erasmusmc.nl
van der Ende
Jan
J
Bongers
Ilja
I
Selten
Jean-Paul
JP
Huizink
Anja
A
Verhulst
Frank C
FC
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D002189:Marijuana Abuse / Q000150:complications / Q000453:epidemiology / Q000523:psychology*; D008385:Marijuana Smoking / Q000009:adverse effects*; D009426:Netherlands / Q000453:epidemiology; D011569:Psychiatric Status Rating Scales; D011599:Psychopathology; D011618:Psychotic Disorders / Q000453:epidemiology / Q000209:etiology* / Q000523:psychology; D012307:Risk Factors; D012565:Schizophrenic Psychology; D011795:Surveys and Questionnaires