No Association Between Cannabis Use Only and Psychosis

By Jeff Hale

A new study published in Drugs and Alcohol Today has found no increased risk for psychosis among individuals who use cannabis and abstain from other “drug use.”

A team of seven researchers from the UK, Ireland, and Denmark set out to explore the association between recreational drug use (cannabis only vs polydrug) and ICD-10 psychotic disorders, noting that few studies have examined the relationship between psychosis and cannabis use in combination with other illicit substances. 

Researchers analyzed self-reported measures of lifetime drug use among 4,718 Danish 24-year-olds. The participants’ reports were linked to the Danish psychiatric registry system which was utilized as an objective mental health status indicator.

Research Findings

“Multivariate binary logistic regression analysis was used to examine the association between drug use (no drug use, cannabis only, cannabis and other drug) and ICD-10 psychotic disorders, while controlling for gender and parental history of psychosis.

Compared with no drug use, the use of cannabis only did not increase the risk of psychosis while the odds ratio for cannabis and other drug were statistically significant.”

Given their findings, researchers proposed that the psychosis risk could be related to the use of multiple psychoactive substances in conjunction.