Considering the lyrics of the many marijuana-inspired songs of the past, like Bob Marley's entreaty not to "worry about a thing," one may not be surprised to learn that recent research posits marijuana as an effective anti-depressant. More surprising, perhaps, are the findings that charge marijuana as the root of depression as well.

The latest research from the laboratory of Dr. Gabriella Gobbi, of the Neurobiological Psychiatry Unit at McGill, implicates marijuana use in inducing both depression and mood improvement. Individuals receiving treatment for marijuana dependence are more likely to have depression, while those seeking treatment for depression also show an increase in marijuana use. These are interesting correlations, but any causal relationship is unclear. Which came first, the depression or the weed? Does marijuana use cause depression, or are depressed individuals more likely to use marijuana?

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