Recent study shows Marijuana not effective for mental health disorders

A large review published in The Lancet Psychiatry by researchers at the University of Sydney found that medicinal cannabis is not an effective treatment for those mental health conditions, despite its widespread use.

While medical cannabis may help with chemotherapy-induced vomiting or muscle spasticity, Dr. Alta DeRoo, Chief Medical Officer at Hazelden Betty Ford, says it is not the answer for mental health disorders.

“Initially, they feel better,” DeRoo explains. “But when they stop, many experience rebound anxiety, insomnia, and depression. It really doesn’t help in the long run.”

Doctors say that cycle can make symptoms more difficult to manage over time—and in some cases, lead to dependence. DeRoo estimates about 10 percent of daily users develop cannabis use disorder, with some patients struggling to maintain work, sleep schedules, or overall stability.

In more serious cases, cannabis use has been linked to psychosis—sometimes requiring intensive or residential treatment.

Health experts are especially concerned about younger users. DeRoo says marijuana use in teens and young adults can trigger psychiatric episodes, particularly for those with a family history of conditions like schizophrenia.

Her advice: seek evidence-based, FDA-approved treatments instead of self-medicating with cannabis.

A closer look at the risks—and how often use turns into a disorder—is coming up in today’s coverage.