People who regularly use cannabis (marijuana) are not at increased risk for suicide, according to a study published December 2009 in the British Journal of Psychiatry. The new research contradicts previous studies that had suggested a link.

Cannabis is often used to treat anxiety and depression, but frequent use can have negative consequences. Several studies have hinted that it might be associated with an increased risk for suicide.

To explore this link, Tomas Hemmingsson, PhD, from the Karolinska Institute in Stockholm, and his colleagues looked at regular surveys of 50,087 men conscripted for Swedish military service during a 33 year period and compared them with the National Cause of Death Register in Sweden.

There were 600 suicides or deaths from undetermined causes during the study period. On first pass, cannabis use was associated with suicide. After controlling for other factors, such as underlying psychological problems, this association was eliminated.

The authors conclude: “These results suggest that cannabis use is unlikely to have a strong effect on risk of completed suicide, either directly or as a consequence of mental health problems secondary to its use.”