At least that's what epidemiologists and psychologists are going to have to do, in light of new findings from the same researchers who found that legalization correlates with fewer road deaths:
"Using state-level data for the period 1990 through 2007, we estimate the effect of legalizing medical marijuana on suicide rates. Our results suggest that the passage of a medical marijuana law is associated with an almost 5 percent reduction in the total suicide rate, an 11 percent reduction in the suicide rate of 20- through 29-year-old males, and a 9 percent reduction in the suicide rate of 30- through 39-year-old males. Estimates of the relationship between legalization and female suicides are less precise and are sensitive to functional form."
That's from the discussion paper, entitled "High on Life? Medical Marijuana Laws and Suicide," written by D. Mark Anderson, Daniel I. Rees, and Joseph J. Sabia, and sponsored by the IZA, a private, independent research institute that conducts nationally- and internationally-oriented labor market research.
Other interesting facts from the paper:
— "Completed suicides, are the tenth leading cause of death in the United States (National Institute of Mental Health 2010)."
— "Alcoholism is associated with suicidal ideation as well as attempted and completed suicides."
— "Females suffer from depression and attempt suicide at higher rates than males ... Nevertheless, males are approximately four times more likely to commit suicide. Since 1990, the male suicide rate has decreased slightly, while the female suicide rate has remained fairly constant."
— "We conclude that the legalization of medical marijuana leads to an improvement in the psychological well-being of young adult males, an improvement that is reflected in fewer suicides."
— "The strong association between alcohol consumption and suicide-related outcomes found by previous researchers raises the possibility that medical marijuana laws reduce the risk of suicide by decreasing alcohol consumption."