Cannabis Use Tied to Worsening of Mania Symptoms

the Psychiatry Advisor take:

Using marijuana can promote the onset of mania symptoms and potentially exacerbate them in those suffering from bipolar disorder.

Steven Marwaha, PhD, of Warwick Medical School, Coventry, United Kingdom, and colleagues reviewed existing studies involving cannabis use. In those six studies, 2,391 individuals had mania symptoms. The mean length of follow-up was 3.9 years.

“We wanted to answer two questions — does cannabis use lead to increased occurrence of mania symptoms or manic episodes in individuals with pre-existing bipolar disorder?,” Marwaha said in a statement. “But also, does cannabis use increase the risk of onset of mania symptoms in those without pre-existing bipolar disorder?”

A review of the literature found that cannabis use preceded or coincided with mania symptoms, rather than cannabis use following mania symptoms, the researchers wrote in the Journal of Affective Disorders. In addition, using marijuana significantly worsened mania symptoms in people diagnosed with bipolar disorder.

A meta-analysis of two studies suggested that cannabis use is associated with an approximately three-fold (Odds Ratio: 2.97; 95% CI: 1.80–4.90) increased risk for the new onset of manic symptoms.

“Our review suggests that cannabis use is a major clinical problem occurring early in the evolving course of bipolar disorder,” Marwaha noted.