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23-05-2012 | Psychology | Article

Cannabis use linked to reduced mortality in psychosis


Free abstract

MedWire News: Study results suggest that cannabis use is associated with decreased all-cause mortality risk in patients with schizophrenia.

Further research is warranted to "shed light on the anti-inflammatory properties of the endocannabinoid system and its role in decreased mortality in people with psychotic disorders," say Maju Mathew Koola (University of Maryland School of Medicine, USA) and colleagues.

The findings come from a study of 762 patients with schizophrenia, schizoaffective disorder, or psychosis not otherwise specified who were aged between 18 and 55 years.

Data on cannabis and alcohol use were gathered from the patients' medical charts and compared with mortality rates over a 4‑10 year period using the Social Security Death Index.

Overall, 295 patients were regular or frequent cannabis users and 478 were regular or frequent consumers of alcohol.

There was no significant difference in Global Assessment of Functioning scores between cannabis users and nonusers, or between alcohol users and nonusers, the researchers note.

In total, 62 patients died during the follow-up period.

After accounting for age, gender, and smoking status, the researchers found that cannabis users had a significantly lower risk for all-cause mortality than nonusers, at a hazard ratio (HR) of 0.5.

Factors associated with increased mortality included male gender, at a HR of 2.2, and older age, at a HR of 2.3 for patients aged 35‑55 years versus those aged less than 35 years.

Alcohol use was not predictive of mortality, the researchers note.

Koola and team conclude in the Journal of Psychiatric Research: "This interesting finding of decreased mortality risk, specifically in cannabis users, is a novel finding and one that will need replication in larger epidemiological studies."

They add: "There is a growing need to understand the long-term effects of cannabis especially because medical marijuana is legal in many states in USA for chronic debilitating medical conditions. Better understanding the risk of mortality in people who are dually diagnosed will enable the field to better target interventions."

By Mark Cowen

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