Study exposes mental effects of pot
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According to the New Scientist, there was hardly enough reliable evidence to support the idea that cannabis use could cause such mental illnesses until now. The lack of good evidence has delayed studies in finding harmful effects of a seemingly harmless drug.
One of the main conclusions of the research was that people who start smoking cannabis as young adults were at the greatest risk of later developing mental health problems. Another study done by an associated team concluded that depression and schizophrenia in the United Kingdom's population could be reduced by 13 percent if marijuana use was eradicated.
The study was done by forming a team that followed 1600 Australian school pupils aged 14 to 15 for seven years. Daily marijuana usage was associated with a fivefold increased risk of depression at the age of 20. The study also concluded that if marijuana was smoked on a weekly basis, there was a twofold increase. The regular users were no more likely to have suffered from depression or anxiety at the start of the study.
Although this study revealed a dose-dependant relationship between the frequency of cannabis use and schizophrenia, the conclusions were relatively vague. So the scientists looked to other factors that would explain the results. They concluded that regular marijuana use led to educational failure and unemployment, which could increase the risk of depression.
"However, because the risk seems confined largely to daily users, the question about a direct pharmacological effect remains," said Australian scientist George Patton, in a recent interview with New Scientist.
Researchers at King's College London, UK, analyzed continuous data taken on over 1000 people born in Dunedin, New Zealand in 1972 and 1973, and found that people who used cannabis by age 16 were four times as likely to have a diagnosis of schizophreniform disorder (a milder version of schizophrenia) at age 27 than those who didn't use the drug.
The study also examined the effects of pregnant women smoking marijuana. The study, conducted on rats, showed that the offspring of pregnant rats given a low dose of cannabinoid were found to perform poorly in learning tests throughout their lives, compared to rats that were not exposed.
This part of the overall marijuana study was done at the La Sapienza University in Rome, and also concluded that long-term learning in the rats was damaged by the cannabinoids irreversibly disrupting chemical and electrical processes in the brain during gestation. According to the New Scientist, the exposed rats were also more hyperactive as infants, although this effect wore off as the rats reached adulthood.
"This is absolutely relevant," says Peter Fried, a psychologist at Carleton University in Ottawa, Canada, who has done similar work in humans, in a recent interview with New Scientist. "What they have found is very consistent with what we have found in humans."
Another study done to see the drug's effects on the lungs was coupled with research done on the long-term mental effects of cannabis usage. According to the New Scientist, The British Lung Council concluded in a recent study that smoking marijuana was as bad if not worse than smoking cigarettes.
For example, the study demonstrated that because of the way marijuana is smoked, three joints a day causes the same damage to the lung's airways as 20 cigarettes. The study also concluded that the amount of smoke taken into the lungs is two thirds larger if cannabis is being smoked. The smoke is also taken one third deeper into the lungs, and that smoke is held an average of four times longer before being exhaled.
Furthermore, the cannabis produced and harvested now had been proven to be 10 to 12 times stronger than the trees smoked in the "flower-power' generation.
By further examining marijuana joints, the scientists found that the tar from a joint contains concentrations of carcinogens benzathracenes and benzpyrenes up to 50 percent higher than tobacco smoke, and that THC, which is the most concentrated psychoactive ingredient of cannabis, destroys the immune system cells that help protect the lungs from infection.
According to The Observer, the study also counters the more relaxed measures taken by governments in response to marijuana. For example, a year ago the British parliament announced plans to reduce the classification of cannabis from category B to C, after a recommendation from the Police Federation that it was far less harmful than other drugs. The reclassification takes place this summer, and anyone caught smoking a joint will be much less likely to be arrested or prosecuted for possession.
Despite the international community's growing acceptance of marijuana -- the drug is legal in Amsterdam, and steps are being taken to legalize it in Canada -- the dangerous effects of the drug are still important to study and note.