BALTIMORE, MD — The use of cannabis is associated with lower mortality risk in patients with schizophrenia and related psychotic disorders, according to a forthcoming study to be published in the Journal of Psychiatric Research.
An international team of investigators from the University of Maryland School of Medicine and Inje University in South Korea assessed the impact of a lifetime history substance use on mortality in 762 subjects with schizophrenia or related disorders.
Researchers reported, “[W]e observed a lower mortality risk-adjusted variable in cannabis-users compared to cannabis non-users despite subjects having similar symptoms and antipsychotic treatments.”
Authors speculated that the association between marijuana use and decreased mortality risk may be because “cannabis users may (be) higher functioning” and because “cannabis itself may have some health benefits.”
They concluded: “To our knowledge, this is one of the first studies to examine the risk of mortality with cannabis and alcohol in people with PD (psychotic disorders). This interesting finding of decreased mortality risk … in cannabis users is a novel finding and one that will need replication in larger epidemiological studies.”
NORML Board Member Dr. Lester Grinspoon, psychiatrist and former Harvard Medical School professor, similarly noted that the study’s findings, though promising, require replication in separate trials. “In reading the cannabis literature over the years, I have learned to be somewhat skeptical about any single report and to maintain a ‘wait and see’ posture as new data eventually flesh out the reality,” he said.
To date the association between cannabis use and psychotic disorders such as schizophrenia is not well understood. While some studies have associated cannabis use with higher cognitive functioning – including better performance on measures of processing speed and verbal skills – other research has implied that cannabis use, particularly heavy use at an early age, may precipitate or exacerbate the disease in those already vulnerable to it. Other experts have criticized this purported link to be “overstated” and not “particularly compelling,” noting that increased levels of cannabis use by the general public has not yet been positively associated with proportionally rising incidences of schizophrenia or other psychotic disorders.