More threads by David Baxter PhD

David Baxter PhD

Late Founder
Cannabis use may prompt transition to psychosis
10 May 2007
Psychiatry Res 2007; 151: 151-154

Cannabis use is strongly associated with the development of psychosis among people at risk of the disorder, research indicates.

The finding supports the notion that cannabis use is a risk factor for schizophrenia and strengthens the case for screening and monitoring at-risk individuals for cannabis use.

Study authors Karin Kristensen and Kristen Cadenhead (University of California at San Diego, La Jolla, USA) tested the link between cannabis use and psychosis among participants in the Cognitive Assessment and Risk Evaluation (CARE) Program.

CARE is a longitudinal program for individuals deemed to be at risk for developing a psychotic disorder, based on the presence of subsyndromal psychotic symptoms, a family history of schizophrenia, and/or a recent deterioration in global functioning.

During 1 year of follow-up, six (12.5%) of the 48 patients made the transition to psychosis. The transition rate was 3.1% among participants reporting no or minimal cannabis use versus 31.3% among those who met criteria for cannabis abuse or dependence.

The difference between cannabis users and non-users was statistically significant, Kristensen and Cadenhead report in the journal Psychiatry Research.

Further analyses found no association between alcohol or cocaine use and the conversion to psychosis; in contrast, nicotine use was significantly tied to later development of psychosis.

The authors admit that their findings are limited by the small sample size and reliance on self-reported measures of cannabis use. They call for future studies to address these limitations.

"Psychoeducation regarding the deleterious effects of cannabis use in vulnerable individuals could discourage use, and perhaps improve outcome," they conclude.



There has been more than enough research to show that using cannabis and it's related components increases ones risk if vulnerable to psychosis.

It most definitely increases psychotic symptoms in those who have a psychotic illness.

I like what one young social worker would say when doing youth education/awareness presentations on schizophrenia.

"If you are smoking pot and have an unpleasant experience then that is an indicator that you should avoid smoking it in the future. You don't want that unpleasant experience to last a lifetime."
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