The study concluded that:
“Cessation of cannabis use was associated with greater psychotic-like experiences, whilst continued cannabis users were more likely to report pleasurable experiences.
“Whereas former users clearly ascribed cessation to negative experiences, continued users who expressed intention to quit less readily ascribed the intention to negative experiences.”
UNODC data suggests that cannabis is used by 6.2% of the UK, roughly 4,030,000 people.
If cannabis use caused psychosis, then surely there would be a similar number of people diagnosed with schizophrenia as there are cannabis users.
According to a leading schizophrenia charity, Living With Schizophrenia: At any one time, about 220,000 people are being treated for schizophrenia in the UK by the NHS.
The numbers clearly do not add up.
However, there is an argument to be had that causation does not lead to correlation.
For example, there are 9.4 million smokers in the UK, but it is projected that only 62,832 cases of lung cancer (32,875 in males, 29,957 in females) will be diagnosed in the UK in 2035.
Dr. Sami admitted that more research will be needed before any definitive conclusions can be made:
“It is important to remember that, at this stage, this is a hypothesis, not a fact.
“The survey was taken at a single point in time and the online sample we had may be different from the average cannabis user.
“But this group were moderate to heavy users, drawn from activist sites and social media – those that we need to engage the most in this kind of work.”
This recent survey puts yet another nail in the coffin for the argument that cannabis use causes schizophrenia, and, in turn, the argument against legalising cannabis, especially for medicinal purposes.
If cannabis does not cause mental illness, then on what grounds would a Government have for maintaining its prohibition of it?
The best study to confirm the hypothesis would be a long-term study mapping cannabis experiences to schizophrenia risk, drawn from the general population, but this would be a long and expensive study to do.
Dr. Sami and his team of researchers are continuing their investigation into cannabis use and mental illness.
If you want to help their research, you can participate by filling out their questionnaire at: thecannabissurvey.com