Cannabis / Marijuana (and other street drugs) Have Been Linked to Significant Increases in a Person’s Risk for Schizophrenia

Street Drugs increase risk of Schizophrenia - use of street drugs (marijuana/hash - cannabis, etc.) have been linked with significantly increased probability of developing schizophrenia. Psychiatrists in inner-city areas speak of cannabis being a factor in up to 80 per cent of schizophrenia cases. Researchers in New Zealand found that those who used cannabis by the age of 15 were more than three times (300%) more likely to develop illnesses such as schizophrenia. Other research has backed this up, showing that cannabis use increases the risk of psychosis by up to 700 per cent for heavy users, and that the risk increases in proportion to the amount of cannabis used (smoked or consumed).

Today, there are over 30 published papers linking marijuana to schizophrenia or other mental disorders. The increase in evidence during the past decade could be tied to the increased potency of marijuana. A review by the British Lung Association says that the cannabis available on the streets today is 15 times more powerful than the joints being smoked three decades ago.

The damage that someone does to their brain by smoking marijuana (or taking other street drugs) when they are younger (under the age of 18) may only become evident later in life; between the ages of 19 and 30, when the person develops schizophrenia.

Schizophrenia can sometimes be triggered by heavy use of hallucinogenic drugs, especially LSD; but it appears that one has to have a predisposition towards developing schizophrenia for this to occur. There is also some evidence suggesting that people suffering from schizophrenia but responding to treatment can have an episode as a result of use of LSD. Methamphetamine and PCP also mimic the symptoms of schizophrenia, and can trigger ongoing symptoms of schizophrenia in those who are vulnerable.

MARIJUANA DOUBLES RISK OF SCHIZOPHRENIA

Smoking cannabis virtually doubles the risk of developing mental illnesses such as schizophrenia, researchers say.

The New Zealand scientists said their study suggested this was probably due to chemical changes in the brain which resulted from smoking the drug. The study, published in the journal Addiction, followed over 1,000 people born in 1977 for 25 years. UK mental health campaigners said it was more evidence of a “drug-induced mental health crisis”.

The researchers, from the University of Otago, interviewed people taking part in the Christchurch Health and Development Study about their cannabis use at the ages of 18, 21 and 25.

They were also interviewed about various aspects of their mental health. The scientists found psychotic symptoms were more common among cannabis users. They analyzed their findings to take into account the possibility illness encouraged people to use more cannabis, rather than the drug contributing to their condition. But the researchers said the link was not likely to be due to people with mental illness having a greater wish to smoke cannabis. Instead, they said cannabis may increase the chances of a person suffering psychosis by causing chemical changes to the brain.

The researchers also took into account factors such as family history, current mental disorders, and illicit substance abuse. ‘Growing evidence’ the scientists, led by Professor David Fergusson, said it was likely cannabis use increased the chances of a person suffering psychosis by causing chemical changes to the brain. Writing in Addiction, he added: “Even when all factors were taken into account, there was a clear increase in rates of psychotic symptoms after the start of regular use.

“These findings add to the growing body of evidence from different sources, all of which suggest that heavy use of cannabis may lead to increased risk of psychotic symptoms and disease in susceptible individuals.” Paul Corry, of the mental health charity Rethink, said: “This is the latest in long line of international research over the last 12 months that shows we are facing a drug-induced mental health crisis.

“Rethink is renewing its call to the Health Select Committee to investigate the latest research into the link between cannabis use and severe mental illness.

“We need action from the Department of Health and we need it now if we are to avoid the risk of tens of thousands of young people developing a severe mental illness in the future.”

Marjorie Wallace, of the mental health charity SANE, said: “At last there is a convincing study supporting what we have been saying for many years, that there is a direct link between cannabis and psychosis.

“We urge the government to reconsider its decision on classification, backing that with a multi-million pound education and awareness campaign on the dangers of cannabis for young people whose brains are developing.”

The Department of Health has said it will review all academic and clinical studies linking cannabis use to mental health problems.

*Above Information provided by schizophrenia.com

These studies have also begun in Canada the following is from StarPhoenix Newspaper in Saskatchewan and the Ottawa Citizen

A pair of articles in the Canadian Journal of Psychiatry has resurrected the “reefer madness” argument about marijuana and its links to mental illness. Cannabis use can trigger schizophrenia in people already vulnerable to the mental illness — and this fact should shape marijuana policy, argue two psychiatric epidemiologists in this month’s journal. The link between marijuana use and schizophrenia is generally accepted in the psychiatric community. The problem is that the vulnerable population — mostly teenagers — generally isn’t eager to absorb the message.

Australian epidemiologists Louisa Degenhardt and Wayne Hall reviewed eight international studies of teens and young adults that examined the link between marijuana use and schizophrenia. They concluded using marijuana can precipitate schizophrenia in users who have a personal or family history of schizophrenia.

One 15-year study of 50,000 young people in Sweden, for example, found those who had tried marijuana by the time they were 18 were 2.4 times more likely to receive a diagnosis of schizophrenia. The Swedish researchers concluded that 13 per cent of schizophrenia cases could be averted if all cannabis use was prevented.

Another study of almost 5,000 subjects in the Netherlands replicated the findings, and also found that marijuana users were more likely to be diagnosed with schizophrenia during the study’s three-year follow-up period. Other studies suggested that subjects who used marijuana in their early teens were more likely to be diagnosed with schizophrenia by their mid-20s.

In a companion article, Hall and Degenhardt argue the evidence has policy implications. Young people should be warned of the marijuana-schizophrenia link, since most schizophrenics are diagnosed by their late teens, about the same time teens are experimenting with cannabis. The link has been used to argue in favour of recriminalizing marijuana in some Australian states. However, only one per cent of the population will be diagnosed with schizophrenia in their lifetimes.

Hall, a researcher at the University of New South Wales in Australia, said it’s a tricky argument to make when, by the numbers, marijuana will adversely affect so few people. But he points out schizophrenia has a high personal and economic cost. Although it’s unlikely that a vulnerable person will develop the illness after puffing on a single joint, Hall said some studies suggest marijuana smokers are two or three times more likely to be diagnosed with schizophrenia. In Australia — where marijuana use is heavy among teens — it’s not uncommon for 20 to 30 per cent of new episodes of schizophrenia to be among patients who use marijuana daily or almost daily.

“There are a lot of other reasons to discourage young people from using cannabis,” said Hall, who believes that young people should know about the link and also be on the lookout for schizophrenic symptoms that show up among their friends who smoke marijuana.

Wende Wood, a psychiatric pharmacist at the Toronto-based Centre for Addiction and Mental Health said people who want to smoke marijuana should wait until they are at least 25. The human brain had developed fully by that time, and if schizophrenia is present, it has usually already become apparent. Young people urgently need better information on the risks cannabis poses to mental health, according to drugs charities.

The call to ministers came three weeks before the government is set to downgrade cannabis from a class B to a class C drug and came after Professor Robin Murray, head of general psychiatry at the Institute of Psychiatry, London, warned its use was now the “number one problem” facing mental health services. Professor Murray told the Times that inner-city psychiatric services were reaching crisis point with up to 80% of new cases of schizophrenia involving a history of cannabis use. He said that four studies published in the last two years found that teenagers who used cannabis were up to seven times more likely to develop a psychotic mental illness such as schizophrenia or manic depression. While the consultant psychiatrist did not oppose reclassification of cannabis, he said the government should do far more to warn people of the possible downside of taking the drug.

The Home Office has commissioned Mentor Foundation UK, a drug use prevention charity, to produce a million leaflets on the health risks of cannabis to be distributed across the country from January 29. But the charity’s chief executive, Eric Carlin said far more needed to be done.

He said: “We need far more preventative services to delay young people from experimenting with drugs until they are able to make informed choices.

“The evidence would seem to support a link between cannabis use and mental health problems, but what exactly the link is unclear. It seems more likely that cannabis use is a trigger rather than a direct cause of psychosis, but we need more research to establish that.”

But an expert on the treatment of patients with mental health and drug problems at the Sainsbury Centre for Mental Health contested claims that downgrading cannabis would lead to far more cases of psychotic illness. Tabitha Lewis, the charity’s practice development and training officer in dual diagnosis, said that despite a few studies that indicated cannabis posed some risk to mental health, the evidence was by no means conclusive.

She said: “I don’t understand how reducing the penalty for using cannabis has any impact on how psychotic it could make you. Nor am I convinced that downgrading the drug will lead to far more people using it.

“What is the alternative to reclassification? Are we really seeking to criminalize our patients? I doubt that staff members report all of their cannabis smoking patients to the police and I doubt the police would respond if they did.”

“We need more robust research if we are to adequately inform young people of the risks.”

Danny Kushlick, director of the Transform Drugs Policy Institute, said that if cannabis did increase the likelihood of some young people experiencing mental health problems, then the government should legalize the drug.

He said: “Cannabis should be sold through licensed outlets with purity listings, health warnings and safer use messages.

“All the evidence shows that the legal status of drugs does little or nothing to influence levels of use. This research should not discourage policy makers from exploring alternatives to criminalization.”

“We should be looking to legally regulate and control the supply of drugs precisely because they are dangerous, not because they are relatively safe for the majority of users.”

It will still be an offence from January 29 to possess, cultivate or supply cannabis, but the maximum sentence for possession will fall from five to two years.

*Article by David Batty Society Garden News