How dope unleashes the demon within
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Using cannabis during adolescence and young adulthood "increases the risk of psychotic symptoms later in life", a recent study found.
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Marijuana is still seen as a "soft" drug, despite growing evidence it can cause severe mental torment - especially among the young. By Jock Cheetham.
Dave's sister worried when he began spending days staring at the backyard. He saw faces in the trees, but she saw nothing. And Dave got angry because the family couldn't see the faces. "I felt like God was talking to me," Dave says. "You know, showing me signs like the clouds in the shape of a peace sign, the faces in the trees, the way the trees used to dance to the music in my head."
Dave, 22, has smoked cannabis since he was 16. He has also used ecstasy. His story fits a disturbing profile. Australians are smoking more - the number of 20-year-olds who have smoked cannabis has trebled in 30 years, the Australian Institute of Health and Welfare says. And Australians are starting younger - almost 40 per cent of those born in the early 1980s had smoked cannabis by the time they reached 16.
Rates of anxiety and depression among young people have risen markedly in each of the past five decades, the Mental Health Council of Australia says. But for some parents who grew up during and since the counter-culture generation, cannabis continues to symbolise freedom, rebellion and broad-minded perspectives. Their views are often based on out-of-date information, says Ian Hickie, a professor of psychiatry at the University of Sydney.
"The social discussion has really been downplayed by people of my generation - middle-aged people who've grown up where smoking cannabis has been an important part of the culture," says Hickie, a board member of the Mental Health Council of Australia. "They have this idea that cannabis is just like alcohol and is our preferred substance of use. It hasn't hurt us so much, so why are we worried."
Two of Hickie's concerns relate to mental illness - depression and the rise in diagnoses of drug-induced psychosis. "Basically, anyone who turns up with a schizophrenia-like illness and they're smoking cannabis and they're taking ecstasy, the first few times we see them, we call (it) drug-induced psychosis. "But if you follow people up, the great majority of them turn out to have schizophrenia, but later on." This lag until the appearance of schizophrenia could be 10 years or more, he says.
The symptoms are disturbing, Hickie says. "Kids who are psychotic have symptoms such as social withdrawal and are not able to form relationships. Typically people will hear voices, they will develop suspicious ideas, they won't trust their family, they'll withdraw from social events, they'll often become quite apathetic."
Dave's illness - diagnosed as drug-induced psychosis - has turned the middle-class family from Sydney's inner west upside down. "It's the hardest thing I've ever had to deal with in my life. And the screaming, the screaming. One night Dave was going off and we were holding the door trying to stop him going out. He has a very abrupt manner, which he never used to be like," says Dave's mother.
She cries as she confesses her guilt over feeling that she neglected her daughter during her final school year because the family was focused on Dave, who has been admitted to hospital four times in two years during psychotic episodes. "At the time he went to hospital, his thoughts were very jumbled."
His father says: "He thought he was either Jesus Christ or a messenger."
"Prophet!" Dave cuts in.
"A prophet of God," his father says. "And he had to save the world. That was his main trip that he was on. He thought he was going to die."
Dave's father says he feels like he has aged 10 years in the past two. "Dave has become very introverted," he says. "We just want him to be like he was. It put a big strain on our (the parents') relationship, too. There were more arguments in the house, before we knew what was going on. I'd always try to pacify and it used to blow up in my face."
Dave left his job in late 2002 and he stopped going to university. He has not worked solidly since. He sold his television, and then began selling everything he owned to buy cannabis. He stole from his parents.
A new study from Maastricht University in the Netherlands has added to the evidence of links between cannabis and psychosis. The study of 2400 young Germans, published two weeks ago in the British Medical Journal, found "exposure to cannabis during adolescence and young adulthood increases the risk of psychotic symptoms later in life". The risk is even greater, the researchers say, for people who are predisposed to psychotic symptoms.
"If you have a family history or a personal history of mental instability you should not use cannabis," says Cecile Henquet, one of the researchers for the Maastricht study. Smoking cannabis before the age of 16 carries a much higher risk of psychotic disorders and the risk rises the more frequently the drug is used.
The Maastricht study conforms with other findings, says Professor David Castle, of the University of Melbourne and the Mental Health Research Institute. "We're finding that more and more of the associations between cannabis and later mental illness, especially psychotic disorders, are being replicated. It's more difficult to say it's one study and one finding and dismiss it."
Once the psychotic episodes have begun, though, the consequences can be severe and long-lasting, Hickie says. "Untreated psychotic episodes can go on for six or 12 months. Stopping drugs is an essential part of managing these conditions, if you can."
But stopping drugs may not be enough to end the psychosis, because they have "precipitated an autonomous brain process, and you've got to treat that brain process". Previously researchers thought that brain development finished by 16 or 17. But modern brain imaging techniques reveal development continues - mainly in the frontal lobes - at least until the early 20s, Hickie says.
The frontal lobes are important in the development of reasoning, developing more sophisticated judgements, understanding of social interactions, and of planning - the higher cognitive functions.
"It's a continuing process," says Hickie. "The earlier the exposure to drugs that may in some way interfere with that process, the more likely it is there'll be harm.
"So the cognitive or emotional changes that precede the onset of psychosis are often happening in 13-, 14-, 15-year-olds. It's absolutely a gradient. The longer you can delay exposure, the less likely it is there will be harm from that exposure. In a public information sense that means emphasising strategies to delay exposure."
The risks are greater because young people are starting to smoke cannabis very young now, says Castle, who edited a recently released book, Marijuana and Madness. "First of all you've got a longer period of exposure. You've also got the situation where you might escalate your use or move on to other drugs.
"If you're impairing those sorts of functions at a critical stage in your intellectual development, i.e., in your teens, when you're setting the template for the rest of your life, you can land up on a very slippery slope.
"Because you're losing that window of opportunity in your teens to develop a whole lot of skills, learn a whole lot of information, get the educational platform that will allow you to go on to higher education, those sorts of things. You never get it back."
Castle and Hickie cite the work of a team led by Professor George Patton, of Victoria's Centre for Adolescent Health, which has linked regular cannabis smoking to depression. The study, also published in the British Medical Journal, found weekly cannabis use in teenagers "predicted an approximately two-fold increase in the risk for later depression and anxiety".
And the study found that "the prevalence of depression and anxiety increased with higher extents of cannabis use, but this pattern was clearest in female participants".
The Melbourne study also challenged the popular hypothesis that people with anxiety or depression self-medicated with cannabis. Not all studies have replicated these findings, and the academics believe more study is needed to confirm the links.
Nonetheless, the rates of anxiety and depression among young people have gone up markedly each decade in the past 50 years, Hickie says. So each generation has higher rates of anxiety and depression than the one before, and also higher rates of substance use.
"That doesn't prove that drugs are the cause," he says. "But one of the hot debates is whether the patterns of substance abuse have driven up the rates of anxiety and depression. And if that were the case you'd see exactly what we're seeing."
Many people are not fully aware of their family's history of mental illness. Dave's father believed his family had no mental illness. But on reflection he recalls that one of Dave's grandmothers and a great-aunt had committed suicide.
These factors were enough to suggest the likelihood of mental illness in the family, says Professor Wayne Hall, of the University of Queensland. In this situation, "I would say don't smoke cannabis, and I would caution about alcohol use, because that's another potent contributor to suicide in people with psychiatric illness".
Dave, who like his family spoke on the condition of anonymity, stopped smoking frequently last month. And his delusions have declined since he was prescribed lithium in hospital, his father says. He has been offered a full-time job in his chosen field after more than two years without regular work. The family is looking positively towards the future.
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