Can cannabis bring people closer to reality? Oddly enough, a new study hints that it can, though possibly in a different way from what you'd expect.

Psychosis is a mental disorder marked by some loss of contact with reality. Psychotic behavior is almost always counterproductive, and people usually benefit when it ceases. But antipsychotic drugs often have serious side effects, both in the young and in the old. That's one reason these drugs are not prescribed to people who are judged at high risk of psychosis but are not yet deemed psychotic.

The scans of the 16 people who received cannabidiol showed partly normalized alterations in three brain regions — the striatum, the parahippocampus and the midbrain.

“There is an urgent need for a safe treatment for young people at risk of psychosis,” says Sagnik Bhattacharyya, lead author of a recent study on psychosis and affiliated with the Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London. He and his research group may have found one — cannabidiol, or CBD, a non-intoxicating component of marijuana that appears to be both safe and very well tolerated.

Studies going back many years have hinted at cannabidiol's effectiveness as an antipsychotic. The current study offers more evidence of this and also shows how cannabidiol might be accomplishing it.

The researchers looked at 33 young people who had not yet been diagnosed with psychosis but who were experiencing some psychotic symptoms, along with 19 healthy young controls. One single dose of cannabidiol (600 milligrams) was given to 16 of the at-risk participants, while the other 17 received a placebo.

All the participants underwent fMRI scans while performing a verbal memory task known to engage three areas of the brain that are involved in psychosis.

Brain scans of the 17 people who had received a placebo were markedly different from those of the control group. But the scans of the 16 people who received cannabidiol were intermediate, suggesting that cannabidiol may have helped relieve some of the causes of psychosis. These scans showed that cannabidiol partly normalized alterations in three brain regions — the striatum, the parahippocampus and the midbrain.

The findings, though based on a rather technical demonstration in a laboratory, as opposed to the outside world, were impressive enough to help these researchers gain funding for a large scale, multi-center, real-world trial that will investigate whether cannabidiol can be successfully used to treat young people at high risk of developing psychosis. If it can, it could pave the way for mainstream adoption of cannabidiol as an antipsychotic drug.

The study appears in JAMA Psychiatry.