January 13, 2009
Twins who are dependent on marijuana are 2.6 to 2.9 times more likely to suffer from suicidal thoughts or attempt suicide than their marijuana dependent co-twin. Marijuana use is also associated with elevated risks of Major Depressive Disorder in dizygotic twins.
Lynskey, M.T., et al. Major depressive disorder, suicidal ideation, and suicide attempt in twins discordant for cannabis dependence and early onset cannabis use. (Archives of General Psychiatry 61(10):1026-1032, 2004.)