Another Study Links Pot Use to Increased Psychosis Development

Smoking pot daily raises psychosis risk,

study finds

Researchers analyzed data from a dozen sites across

Europe and Brazil from 2010 to 2015

The Associated Press 

Experts say the new study's findings have implications for jurisdictions legalizing marijuana

Smoking high-potency marijuana every day could increase the chances of developing psychosis by nearly five times, according to the biggest-ever study to examine the impact of pot on psychotic disorder rates.

The research adds to previous studies that have found links between marijuana and mental health problems, but still does not definitively pinpoint marijuana as the cause.

Psychotic disorders — in which people lose touch with reality — are typically triggered by factors including genetics and the environment. But experts say the new study's findings have implications for jurisdictions legalizing marijuana, warning they should consider the potential impact on their mental health services.

"If we think there's something particular about (high-potency) cannabis, then making that harder to get a hold of, could be a useful harm-reduction measure," said Suzanne Gage, of the University of Liverpool, who was not connected to the new study.

Researchers at King's College London and elsewhere analyzed data from a dozen sites across Europe and Brazil from 2010 to 2015. About 900 people who were diagnosed with a first episode of the disorder at a mental health clinic, including those with delusions and hallucinations, were compared with more than 1,200 healthy patients. After surveying the patients about their use of cannabis and other drugs, researchers found daily marijuana use was more common among patients with a first episode of psychosis compared with the healthy, control group.

Regular pot users 3X danger

Strong pot users 5X danger

Teens with heavy use of pot 8X danger

The scientists estimated that people who smoked marijuana on a daily basis were three times more likely to be diagnosed with psychosis compared with people who never used the drug. For those who used high-potency marijuana daily, the risk jumped to nearly five times. The paper was published online Tuesday by the journal Lancet. It was paid for by funders including Britain's Medical Research Council, the Sao Paulo Research Foundation and the Wellcome Trust.

"If you decide to use high-potency marijuana, you should bear in mind: Psychosis is a potential risk," said Dr. Marta Di Forti, of King's College London and the study's lead author. She said it was unknown how frequently people could smoke lower-potency marijuana without raising their likelihood of psychosis, but that less than weekly use appeared to pose no risk.

Di Forti and colleagues estimated that in Amsterdam, about half of new psychosis cases were associated with smoking high-potency pot.

Gage noted that it was possible that people with a family history of psychosis or other risk factors might be more susceptible to developing problems like psychosis or schizophrenia if they used cannabis.

"That could be the thing that tips the scale for some people," she said. "Cannabis for them could be an extra risk factor, but it definitely doesn't have to be involved. If you use cannabis, it doesn't mean you are definitely going to develop psychosis."

No age groups in study!

It just means you are playing Russian Roulette with your sanity and your future, especially if you are a teenager. This study, unfortunately, doesn't break down the risks to various age groups, but other studies show a dramatic increase in the risk of Schizophrenia developing in teens who use pot. At least one expert says there is a one in six probability of young teens developing full-blown Schizophrenia from using pot.

"If you smoke a lot of marijuana when you are young

or in your teens, your chance of having psychosis later

on in life is about eight times higher than other people,"

Dr. Bill MacEwan, assistant director of UBC's dept. of psychiatry

'The Link Between Marijuana and Psychosis is Significant'

Gabriel Klein's tale hints at dark truth of chronic pot use on 'susceptible' young brains, doctor says

Gabriel Klein is a young man who walked into an Abbotsford High School and stabbed two young girls, one of them, Letisha Reimer, to death. Klein was a complete stranger to anyone in the school and had no interaction with the girls before attacking them. Letisha was buried yesterday with a crowd of more than a thousand people in attendance.

I live in Abbotsford, British Columbia and, in fact, the helicopter that transported the girls to the hospital flew right over my car shortly after take-off as I happened to be less than a block away. 

'The link between marijuana and psychosis is significant' says UBC psychiatrist Dr. Bill MacEwan

By Yvette Brend, CBC News 

Canadian youth have the highest rate of marijuana use in the developed world and marijuana is the most commonly-used illegal drug among Canadians aged 15 to 24 years. 

Gabriel Klein's friends say he was smoking pot every day for the past three months.

Then one day the 21-year-old changed.

A few weeks later — on Nov. 1 —  he was accused of walking into a high school and stabbing Letisha Reimer, 13, and another teen.

Klein was admitted to hospital after his arrest, certified under the Mental Health Act by one doctor and then decertified by a psychiatrist the next day, the prosecutor said.

Details about exactly what drugs Klein was using and his mental state are still emerging, but for Dr. Bill MacEwan the facts, so far, hint at the darker reality of heavy drug use for a certain percentage of chronic young pot smokers.

Homicide investigators released this photo early in the investigation, which they say shows Gabriel Klein at an undisclosed location, just hours before the fatal stabbing. (IHIT/Twitter)

While the assistant director of UBC's department of psychiatry stresses that the percentage is tiny, he and others who study the link between pot and psychosis say it should be part of the conversation.

Marijuana — framed of late as medicinal, mainstream and benign — is in common use amongst Canadian youth, who have the highest rate of pot use in the developed world for those aged 15 to 24, according to the Canadian Centre on Substance Abuse.

And while most smokers who start using while their brain is developing risk impaired learning and motor skills, a tiny percentage of people who smoke pot — one to three per cent — will also experience psychosis.

Playing Russian Roulette with your brain

Dr. MacEwan says the ratio approaches 30 to 40 per cent in a sub-set of young chronic pot smokers who have other risk factors.

It's worse if the person is homeless, stressed and using a cocktail of chemicals daily.

For them, MacEwan says, it's like playing Russian roulette with their brain.

"The link between marijuana and psychosis is significant," says Dr. William MacEwan of UBC's psychiatry department. (Cliff Shim/CBC)

A youth who is smoking excessive amounts, unsure what they are smoking and using marijuana to cope with stress, are at highest risk, MacEwan said.

"Psychosis in a drug-induced state is really quite common, particularly amongst vulnerable youth such as this young man.They will often have to use drugs, particularly drugs like cocaine and methamphetamine, to stay awake at night. They will often used drugs to cope with stress and those that are under really difficult situations like being homeless ... then the drugs will affect you worse."

In addition schizophrenia, unlike other mental illnesses, emerges in young adulthood — usually in the early 20s for men and later for women, and it's believed pot speeds the progression.

"Emerging evidence supports a number of associations between cannabis and psychosis/psychotic disorders, including schizophrenia," according to a 2014 review of the association between cannabis and psychosis led by Dr. Rajiv Radhakrishnan from Yale's School of Medicine.

A debate rages with many scientists saying abolishing pot would not prevent schizophrenia, and marijuana advocates deeming this a "scare tactic," claiming pot actually helps soothe anxiety and calm mental disorders.

But medical experts contend it is clear that for some smokers who start young,  heavy drug-use can precipitate psychosis,

For the lucky, it's temporary. For others, it's the first bout of a life-long struggle with schizophrenia.

"In some brains, we don't understand exactly why, we think maybe genetics or maybe trauma in the past, that these brains are then really susceptible to having the effects of drugs make them lose touch with reality," said MacEwan.

"The link between marijuana and particularly psychosis is significant." 

A protester lights a joint during a 4-20 marijuana rally on Parliament Hill. (Sean Kilpatrick/Canadian Press)

Some medical experts urge pot-avoidance under age 20, in case their brain has hidden vulnerabilities that will only emerge with drug use.

"Not every 14-year-old who smokes marijuana will have schizophrenia," said Dr. Romina Mizrahi, a director of the Youth Psychosis Prevention clinic at the Centre for Addiction and Mental Health in Toronto.

She explains a myriad of factors — from genetics to trauma history — determine the risk to an individual. 

Variables from marijuana strength, user frequency to how young they are when they start, all play a part. 

A girl smokes a joint at the 4-20 event in downtown Vancouver, B.C., on Monday, April 20, 2015. (Jonathan Hayward/The Canadian Press)

Chance of psychosis 8 times higher

"If you smoke a lot of marijuana when you are young or in your teens, your chance of having psychosis later on in life is about eight times higher than other people," MacEwan said research has shown.

He suddenly changed

Klein's friends describe him as a genial "stoner."

He had no fixed address but lived at Covenant House, followed the rules and worked hard in school.

Then one night he "smoked a bowl" and told his friend Nathaniel Spidell the pot was spiked with acid or something stronger.

Spidell said his friend became fearful and paranoid.

"Everything went downhill after that. He wasn't the same person," said the 23-year-old.

From the outside, people see a person withdraw in a "fearful, angry, irritable way," said MacEwan.

"That young man's friends saying, 'oh he isn't the way he used to be' — is typical."

And that makes it worse, because the person can't relate to people who could help them.

While violence isn't the norm, it can be a result of untreated psychosis.

Klein's friends say they do not recognize the man they see in the video as Klein.

He is nothing like the friend they knew, but that's exactly what psychosis looks like. 

A stranger — perhaps even in the mirror.

    'I could just never imagine him being a violent person,' said Jordan Reid, 23 (right) standing
    with Nathaniel Spidell (left). (Kamil Karamali/CBC)