Cannabis use and outcome of recent onset psychosis.
OBJECTIVE
To test the hypothesis that recent onset psychotic patients who use cannabis will have psychotic symptoms that are more severe and more persistent than those who do not use cannabis.


METHODS
We carried out a 4-year follow-up study of a cohort of 119 patients with recent onset of psychosis. The patients were divided into four groups according to duration of cannabis use, taking index admission and follow-up as reference points.


RESULTS
Those subjects who persisted in the use of cannabis had more positive (but not negative) symptoms and a more continuous illness at follow-up.


CONCLUSIONS
The main limitations of the study were: the relatively small sample size, and that the excess of male subjects and the presence of cannabis induced psychosis could have a confusing impact on the interpretation of the results.


CONCLUSIONS
It is possible that psychotic patients who use cannabis are at a greater risk of a more continuous illness with more positive symptoms than those who do not.
Grech
Anton
A
Department of Psychiatry, Mount Carmel Hospital, Malta. antongrech@waldonet.net.mt
Van Os
Jim
J
Jones
Peter B
PB
Lewis
Shon W
SW
Murray
Robin M
RM
D000328:Adult; D000437:Alcoholism / Q000453:epidemiology / Q000523:psychology; D010054:Brief Psychiatric Rating Scale; D015331:Cohort Studies; D015897:Comorbidity; D003702:Delusions / Q000453:epidemiology / Q000523:psychology; D005260:Female; D005500:Follow-Up Studies; D006212:Hallucinations / Q000453:epidemiology / Q000523:psychology; D006801:Humans; D013287:Illicit Drugs; D008297:Male; D008385:Marijuana Smoking / Q000009:adverse effects / Q000453:epidemiology* / Q000523:psychology; D016017:Odds Ratio; D017063:Outcome Assessment, Health Care; D010343:Patient Admission; D011379:Prognosis; D012559:Schizophrenia / Q000175:diagnosis / Q000453:epidemiology*; D012565:Schizophrenic Psychology; D019966:Substance-Related Disorders / Q000453:epidemiology / Q000523:psychology
D013287:Illicit Drugs