Legalization of medical marijuana has been found to correlate to a significant drop in suicide rates, providing additional evidence that the federally outlawed substance may have a positive effect on U.S. public health.

The new study, which is published in the American Journal of Public Health, shows that the suicide rate among men ages 20 to 29 and 30 to 39 fell by 10.8 percent and 9.8 percent respectively following a given state’s decision to legalize medical marijuana. Although the relationship was weaker and less precise among women, the authors believe that the findings provide strong evidence in favor of medical cannabis. “The negative relationship between legalization and suicides among young men is consistent with the hypothesis that marijuana can be used to cope with stressful life events,” they wrote.

To investigate, the team looked at suicide rates per 100,000 people in a set of states allowing medical marijuana as well as a group of control states in which the drug is still illegal. Using data from the National Vital Statistics System’s Mortality Detail Files, they were able to graph a six-year trend beginning three years before the law change and ending three years after.

The researchers found that, in the years leading up to the new law, the male suicide trend was largely the same across all surveyed states. But as soon as medical marijuana was introduced, state trends began to diverge, with legalizing states recording a drop and non-legalizing states recording a surge. On average, states that legalized the medicinal use of the drug cut the male suicide rate from 27.2 per 100,000 men to 23.5 in the three years following the law change.

“Opponents of legalizing medical marijuana point to the large number of studies showing that marijuana use is positively associated with depression, the onset of panic attacks, psychosis, schizophrenia, and suicidal ideation,” the authors explained. “However, the association between marijuana use and outcomes such as these could be attributable to difficult-to-measure confounders such as personality.”

According to the Mayo Clinic, there is “good scientific evidence” that the medical marijuana can be used as palliative treatment for multiple sclerosis and other conditions involving chronic nerve and muscle pain. That said, success stories from patients suggest that the drug can help alleviate an even broader range of symptoms, including seizures associated with epilepsy. One example is Charlotte Figi, a 6-year-old with epilepsy whose life was transformed by a course of low-THC cannabis oil.

 

Source: Anderson M, Rees DI, Sabia J. Medical Marijuana Laws by Gender and Age. American Journal of Public Health. 2014.