As the medical uses of cannabis become more widely accepted and understood, there's been a surge of interest in whether it can effectively treat mental health conditions ranging from Seasonal Affective Disorder to depression and anorexia. While cannabis has also been linked with negative mental health effects like early-onset psychosis, some suggest cannabis could benefit certain people suffering from bipolar disorder.
First, the good news: cannabis use could boost verbal fluency and learning in individuals with bipolar. A 2010 study of 133 patients by researchers at the University of Oslo found that cannabis users regularly outperformed non-users on these two skills (although the improvements in learning were, it must be noted, slight).
These findings support those of a 2012 study at New York's Zucker Hillside Hospital, which linked regular marijuana use with higher levels of attention, processing speed, and memory among the 200 bipolar patients over a span of nine years.
This is a good news, bad news story for cannabis
Now, the bad news: a study by the International Mood Disorders Research Center in Spain found patients who quit cannabis during treatment for manic/mixed bipolar episodes significantly improved their day-to-day functioning. Those who stayed off cannabis during a maintenance treatment program also found their symptoms were less likely to reoccur.
These results, at least, suggest it might be a good idea for sufferers to nix cannabis during manic/hypomanic episodes.
For now, the jury's out on whether cannabis helps or hinders managing bipolar - but it appears the effects depend largely on what's already happening in the brain. A small study published in PLOS One found "cannabis use [was] associated with both positive and negative emotional states," according to lead researcher, Dr. Elizabeth Tyler.
But we do know one thing: cannabis is used more frequently by individuals with bipolar than among the general population, indicating at least on an anecdotal level that it provides relief. And if it does work, it may have fewer side-effects than drugs like lithium and antidepressants.
Only further study will indicate the long-term effects of cannabis on patients with bipolar - and, as with all medications, it's something patients should discuss with their doctors as part of a broader treatment plan.