Risks of cannabis use for mental health treatment outweigh benefits

New study shows evidence of positive outcomes is scarce while symptoms can be exacerbated

The use of cannabis medicines to treat people with depression, anxiety, psychosis or other mental health issues cannot be justified because there is little evidence that they work or are safe, according to a major new study.

A review of evidence from trials conducted over nearly 40 years, published in the journal Lancet Psychiatry, concludes that the risks outweigh the benefits. And yet, say the authors, they are being given to people with mental health problems in Australia, the US and Canada, and demand is likely to grow.