Medicinal cannabis ‘does not help depression and anxiety’

Using medicinal cannabis to treat people with mental health issues cannot be justified because there is little evidence that it works or is safe, according to a major new study.

The authors of the report, published in Lancet Psychiatry, analysed the results of a total of 83 trials dating back 40 years into the effects of medicinal cannabinoids on patients with conditions including depression, anxiety, attention-deficit hyperactivity disorder (ADHD), Tourette syndrome, post-traumatic stress disorder (PTSD) and psychosis.

The team of researchers, from Australia, concluded that evidence of a positive effect was rare. And THC, one of the derivatives of cannabis, was found to made people with psychosis worse, The Guardian reports.

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The study authors say “a large body of research” suggests that cannabis use “can increase the occurrence of depression, anxiety, and psychotic symptom”.

“Further high-quality studies directly examining the effect of cannabinoids on treating mental disorders are needed,” they add.

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As Time magazine points out, the news comes as marijuana is “more mainstream than it’s ever been” with a growing number of US states “legalising it medicinally and recreationally”, millions of people “vaping products that contain the compound THC”, and non-psychoactive CBD “in everything from beauty products to seltzer water”.

In an article in Lancet Psychiatry commenting on the findings, psychiatry professor Dr Deepak Cyril D’Souza of Yale University School of Medicine argues that “in light of the paucity of evidence, the absence of good quality evidence for efficacy, and the known risk of cannabinoids, their use as treatments for psychiatric disorders cannot be justified at present”.

Earlier this year, new research connected marijuana use among teenagers to depression and suicide in early adulthood. Researchers found that “the odds of attempting suicide were almost 3.5 times worse among those who used cannabis before the age of 18 than those who did not,” according to The Guardian.