One of the most popular arguments raised by cannabis prohibitionists is that cannabis is synonymous with psychosis. Academic expert, Ian Hamilton, concludes that research shows there is a ‘weak’ link between cannabis use and mental health problems. Thus, cannabis psychosis would be rare.
Hamilton, a York University lecturer in mental health, reviewed existing research to draw his conclusions. The Independent interviewed him about his findings. He told journalists that cannabis psychosis had been investigated since the 60’s when the idea first became popular. As a result, he had a lot of source material to work from.
A recent review concludes that the risk of cannabis causing mental illness is weak. To illustrate, 23,000 people would have to be prevented from using cannabis in order to avoid one case of psychosis.
However, Hamilton warns that these studies were done when low potency cannabis was around and not “skunk.” Few studies have been conducted on high potency cannabis. These high potency strains contain less CBD. This cannabinoid offers protection against psychosis caused by THC, which is believed to trigger psychosis.
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Cannabis psychosis: more use higher risk
It is clear says Hamilton, that the more cannabis a person uses, the higher the risk of psychosis becomes. He says only 9% of cannabis users consume 73% of cannabis. Using cannabis aggravates symptoms of schizophrenia. He suggests regulation that could introduce some form of quality control. Users could be provided with information about the strength of the cannabis instead of only discovering how potent it is after they use it.
Greatest risk tobacco
The trend in the UK is for people to mix tobacco with cannabis and this is the biggest risk, as many youngsters are introduced to tobacco in this way, says Mr. Hamilton. In the US the risk of developing tobacco dependence is smaller as people are more likely to use cannabis on its own.
Information about these risks could be communicated if regulation were in place rather than the focus being on the prohibition of cannabis under the Misuse of the Drugs Act.
Hamilton concluded that the link between cannabis and psychosis has been difficult to communicate and is weak. The clearest advice he would give, with the greatest potential health benefit, is to avoid using tobacco with cannabis when smoking joints.
Highest cannabis use countries have the lowest schizophrenia
As a reader rightfully comments, the countries with the highest cannabis use have some of the lowest rates of schizophrenia. For instance, Iceland is rated the highest per capita cannabis user in the world and is right down on the schizophrenia list at 191st. Singapore, on the other hand, is 7th on the schizophrenia list, but rates lowest on the world cannabis use list.
More use doesn’t increase schizophrenia cases
Schizophrenia affects about 1% of any population and has not increased since scientists set the benchmark. Since then, cannabis use has become popular with as many as 40% of people, but schizophrenia figures haven’t budged. Wayne Hall of the University of Queensland found no increase in the number of schizophrenia cases in Australia, despite the massive increase in the number of Australians using cannabis since the 60’s.
It seems likely that high THC cannabis can trigger pre-existing psychosis, but whether cannabis psychosis exists on its own remains unproven. As for CBD, some scientists even believe that it has an anti-psychotic effect. At all events, it’s probably best to avoid high-potency skunk – just in case.