More Self-Harm by Younger Men.

• Position: LEGALIZED MARIJUANA

States that legalize recreational marijuana use, and in some cases allow retail sales of the drug, may see more suicide attempts and other self-harm among younger men, suggests a study published in JAMA Network Open.

Researchers examined whether rates of self-harm injuries--which include suicide attempts and non-suicidal behaviors like cutting--correlate with changing marijuana laws and found an increase among men younger than 40 in states that allow recreational use. The study indicates no such correlation with states that allow only medical marijuana use.

"States that legalize, but still constrain commercialization may be better positioned to protect populations from unintended harms," says senior author Keith Humphreys, professor of psychiatry and behavioral sciences at the Stanford University School of Medicine.

Humphreys, who worked as senior policy adviser for the White House Office of National Drug Control Policy from 2009-10 under the Obama Administration, says there is little research available on the health effects of the legalization of the recreational use of marijuana.

In certain states, this allows the opening of for-profit dispensaries that sell unregulated varieties of strains and dosages of the drug. The study showed that in states that legalized...