Pubdate: Mon, 16 Feb 2015
Source: Daily Telegraph (UK)
Copyright: 2015 Telegraph Media Group Limited
Authors: John Bingham, Peter Dominiczak, and Camilla Turner


Study Finds 60,000 Britons Are Living With Mental Illness Because of 
Super-Strong Drug

ONE in four new cases of psychotic conditions such as schizophrenia 
could be the direct result of smoking extra-strong varieties of 
cannabis, a major new study concludes.

The finding suggests that about 60,000 people in Britain are 
currently living with conditions involving hallucinations and 
paranoid episodes brought on by abuse of high-potency cannabis, known 
as skunk, and more than 300,000 people who have smoked skunk will 
experience such problems in their lifetime.

The six-year study, the first of its kind in Britain, calculates that 
daily users of skunk are five times more likely to suffer psychosis 
than those who never touch it.

Psychiatrists said there is now an "urgent need" for a drive to 
educate the public about the risks involved with the substance. It is 
believed that even newer varieties, some of them more than twice as 
potent as those currently available on British streets, have already 
been developed in the Netherlands.

The findings reopen the debate about the classification of cannabis 
as an illegal drug, with some supporters of liberalisation now 
considering tougher restrictions on some varieties.

Chris Grayling, the Justice Secretary, said the findings underlined 
arguments against decriminalisation.

Norman Baker, the Liberal Democrat former Home Office minister who 
has called for drug laws to be relaxed, said that there may be a case 
for giving skunk a new classification.

The study, by researchers from the Institute of Psychiatry, 
Psychology & Neuroscience at King's College London, is due to be 
published in the journal Lancet Psychiatry later this week. They 
studied almost 800 working-age adults from one area of south London, 
half of whom had been recently treated for a psychotic episode for 
the first time.

The incidence of schizophrenia in the area has doubled since the 
mid-Sixties, a trend widely thought to be linked to drug use.

Cannabis use in the UK overall has fallen by about 40 per cent in the 
past decade but, for those using it, the typical potency has 
increased sharply in that time.

Levels of tetrahydrocannabinol (or THC), the main psychoactive 
compound, are about 15 per cent in skunk, compared with about four 
per cent in traditional "hash" cannabis.

The study concluded that the strength of cannabis and the frequency 
of use play a crucial role in determining the mental health risks.

"Compared with those who never used cannabis, individuals who mostly 
used skunk-like cannabis were nearly twice as likely to be diagnosed 
with a psychotic disorder if they used it less than once per week, 
almost three times as likely if they used it at weekends, and more 
than five times as likely if they were daily users," the paper notes.

It found that skunk use was the "strongest predictor" of psychotic 
illness in those studied and that 24 per cent of new cases in the 
area could be attributed to skunk. It also noted that those who 
started smoking cannabis before the age of 15 had higher risk of 
developing psychotic disorders than others.

"Our findings show the importance of raising public awareness of the 
risk associated with use of high-potency cannabis, especially when 
such varieties of cannabis are becoming more available," the paper concludes.

"The worldwide trend of liberalisation of the legal constraints on 
the use of cannabis further emphasises the urgent need to develop 
public education to inform young people about the risks of 
high-potency cannabis."

Dr Marta Di Forti, the lead author, said the significance of how 
regularly people smoked cannabis has often been overlooked in 
day-to-day treatment. "When a GP or psychiatrist asks if a patient 
uses cannabis it's not helpful - it's like asking whether someone 
drinks," she said.

"As with alcohol, the relevant questions are how often and what type 
of cannabis." Prof Sir Robin Murray, professor of psychiatric 
research at King's, said: "It is now well known that use of cannabis 
increases the risk of psychosis. However, sceptics still claim that 
this is not an important cause of schizophrenia-like psychosis.

"This paper suggests that we could prevent almost one quarter of 
cases of psychosis if no-one smoked high-potency cannabis."

He added: "Education is the important thing - people need to know the 
risks of regular use of high-potency cannabis.

Mr Grayling said: "Far too many of those who end up in our criminal 
justice system have got drug and mental health problems.

"It's clear to me that drug addiction is at the root of a large 
proportion of crimes in the UK and that it causes mental health 
problems which are all too apparent in our prisons.

"That's why mental health will be our next big reform focus - but 
it's also why decriminalisation is not the right option."

Mark Winstanley, the chief executive of Rethink Mental Illness, said: 
"Essentially, smoking cannabis is like playing a very real game of 
Russian roulette with your mental health. Reclassifying cannabis 
isn't the answer."

A Home Office spokesman said: "Our approach remains clear: we must 
prevent drug use in our communities and help dependent individuals 
through treatment and recovery, while ensuring law enforcement 
protects society by stopping supply and tackling the organised crime 
that is associated with the drugs trade."
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