Pubdate: Mon, 16 Feb 2015
Source: Independent  (UK)
Copyright: 2015 Independent Newspapers (UK) Ltd.
Author: Matthew Moore


Nearly a quarter of new cases of psychosis are linked to highpotency 
"skunk like" cannabis, new research shows.

People who smoke superstrength cannabis are three times more likely 
to develop psychosis than people who have never tried the drug  and 
five times more likely if they smoke it every day.

The study, by researchers at King's College London, will fuel calls 
for politicians and public health officials to take a stronger stance 
against high potency cannabis, at a time when many campaigners are 
arguing for marijuana to be legalised. The researchers say there is 
an "urgent need" to inform young people about the risks of strong cannabis.

Uruguay and the US state of Colorado have legalised cannabis use in 
recent years, but there is mounting evidence that strong types of the 
drug can trigger mental illness.

"This paper suggests that we could prevent almost one quarter of 
cases of psychosis if no-one smoked high potency cannabis. This could 
save young patients a lot of suffering and the NHS a lot of money," 
said Sir Robin Murray, Professor of Psychiatric Research at Institute 
of Psychiatry, Psychology & Neuroscience at King's, which carried out 
the research.

Dr Marta Di Forti from the IoPPN, who was lead author on the 
research, said GPs should ask their patients what type of cannabis 
they smoke, to clarify the risk of psychosis. The study found that 
smoking hash, a less potent form of cannabis, had no association with 

The research is published in Lancet Psychiatry.
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