Latest JAMA Studies Largely Fail to Support Past Claims About Marijuana and Brain Health

Two new studies published online this week in JAMA (Journal of the American Medical Association) Psychiatry provide little support for previous claims that cannabis exposure is significantly harmful to the developing brain.

The first study, which assessed the effects of cannabis exposure on brain volume in exposed and unexposed sibling pairs, reported that any identifiable differences “were attributable to common predispositional factors, genetic or environmental in origin.” By contrast, authors found “no evidence for the causal…