December 2, 2009
“˜Skunk’ Cannabis Poses Greater Risk Of Psychotic Illness
New research suggests that those smoking potent "skunk" marijuana have a greater chance of developing psychotic illnesses like schizophrenia than people smoking other types of cannabis.
The research shows that regular users have twice the risk of developing psychosis, while skunk users increase their risk by seven-fold.
The findings, published in British Journal of Psychiatry, come only weeks after the UK's chief drugs adviser was fired after criticizing the government's decision to reclassify cannabis up to Class B from C.
The authors of the new research from the Institute of Psychiatry were sure to clarify that they have no agenda in their research other than to provide information of the subject.
They also point out that drug use only accounts for somewhere between 10 and 15 percent of the cases of psychotic illnesses. There are other risk factors, such as family history of mental health problems that play a far bigger role.
However, they said cannabis and the stronger version skunk should be considered a potential health risk like alcohol.
They explained that in the same way drinking excessive amounts of liquor every day is more of a health risk than a half glass of wine in the evening, smoking the potent skunk daily is more risky than smoking less strong types of cannabis occasionally.
Dr. Marta Di Forti and colleagues at the Institute of Psychiatry found that almost 80% of the 280 patients they screened when admitting them to their hospital presenting psychotic symptoms for the first time were heavy skunk users.
The team also interviewed healthy controls of a comparable age and social background, who they found through newspaper ads and the internet, about their drug habits.
There was no significant difference between either groups in whether they had ever used cannabis or their age at first use, but the patients with psychosis were twice as likely to have used cannabis for more than five years, and over six times more likely to use it every day.
With cannabis users, psychosis patients were seven times more likely to use skunk than the controls.
UK experts have theorized that the composition of skunk may have something to do with it, since it has a greater level of chemicals, or THC, that get users high.
THC is the primary psychoactive ingredient and has been proven to bring out psychotic symptoms like hallucinations and delusions in experiments.
Hashish, which is comprised of cannabis resin, is different than skunk in that it contains substantial quantities of another chemical called cannabidiol or CBD and research suggests this can effectively counteract the psychotic side effects of the THC.
Di Forte said their findings were alarming, especially since skunk has overwhelmed the UK cannabis market in recent years.
"Public education about the risks of heavy use of high-potency cannabis is vital."
While experts do know that risks increase with both duration and amount of cannabis use, Di Forte added that more research needs to be done to determine the exact risks of smoking different types and amounts of the drug.
There has been a broad range of responses on the issue from various groups.
A spokesman from The Legalize Cannabis Alliance UK said, "We don't need to worry about the health harms of people smoking cannabis per se, whether it is skunk or not. What is a concern is that as a result of prohibition some dealers put other stuff into the cannabis they sell that may be damaging. I've heard of lead and glass being put in it."
Chris Hudson, addictions expert at the charity Frank said, "You never truly know what you're getting and stronger cannabis, such as skunk, can increase the chance of suffering a nasty reaction."
A Home Office spokesman commented, "The reclassification of cannabis as a Class B drug was partly in response to emerging concerns about the growing use of stronger strains of cannabis, such as skunk, and the harm they may cause to users' mental health."
"We remain determined to crack down on all illegal substances and minimize their harm to health and society as a whole."
Marjorie Wallace of the mental health charity SANE said, "We receives daily evidence that the long-term use of skunk, with its specific chemical make-up, can trigger frightening psychotic episodes, cause relapse and may bring about mental conditions such as schizophrenia.
"It can also rob developing young minds of their potential and wreck their futures and those of their families."
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