New study finds no link between cannabis and psychosis

• Research from the U.K., Ireland and Denmark may have debunked one of the strongest arguments against cannabis
• The study found no increased risk for psychosis in cannabis users who abstain from other “drug use”

A new study, published in Drugs and Alcohol Today, has claimed that there is no increased risk for psychosis for those who only use cannabis.

The study sought to examine the association between recreational drug use and psychotic disorders, e.g. cannabis use and psychosis. However, this study uniquely looked into the relationship between cannabis use and psychosis, whilst examining this relationship within a “polydrug” context, i.e. combining cannabis with other drugs – such as tobacco, alcohol or cocaine. The research team, made up of seven researchers from the U.K., Denmark and Ireland, analysed 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.

What the researchers found may finally debunk the “cannabis causes psychosis” argument, which is often used to justify keeping it illegal:

“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.”

If cannabis use, on its own, does not cause psychosis, will the British Government be forced to legalise, as the apparent link between cannabis use and psychosis seems to be the only strong argument for maintaining prohibition?