There are many, many studies linking cannabis use to schizophrenia and psychosis – including one recently that suggests it is the latter (or at least a latent predisposition towards the latter) that influences the former rather than vice versa.
Now, research reveals there is a naturally occurring component within cannabis that can actually help suppress symptoms of psychosis, at least in the short-term. The study has been published in JAMA Psychiatry.
The substance in question is cannabidiol (CBD), and one dose may be all it takes to alleviate certain brain abnormalities, including delusions and hallucinations. It is the very same cannabinoid that has been purified and licensed by the FDA as a treatment for rare and severe forms of epilepsy.
To study its effects on psychosis, scientists from King's College London (KCL) recruited 33 young people who had been experiencing distressing psychotic symptoms but were not yet diagnosed with psychosis and a further 19 to act as controls. Sixteen of the at-risk group were offered a single dose of cannabidiol (600 mg). Everyone else took a placebo.
Three hours later, volunteers performed a memory task while their brain was being scanned by an MRI machine. The task had been specifically designed to engage three parts of the brain connected to psychosis, including activities such as saying whether or not a pair of words went well together, then recalling which word had been paired with which.
The 33 young people with psychosis-like symptoms continued to show higher levels of abnormal brain activity in these brain regions than the control group (unsurprising), but those who had taken the cannabidiol supplement showed lower levels than those who had taken the placebo.