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Information & Facts About Marijuana Use and Mental Illness
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Marijuana gives most people a pleasant "buzz" or high, while others develop paranoia and sometimes psychosis, involving a frightening break from reality, heightened anxiety and hallucinations - symptoms of schizophrenia.
THC triggers an increase in a brain chemical called dopamine, which controls mood. An increase in dopamine makes us more aware, and that heightened awareness can lead to the hallucinations associated with schizophrenia.
Marijuana cannot cause mental illness on its own. It is one of a number of risk factors, which include: 1) a family history of mental illness, 2) a "psychosis-prone" personality, 3) a history of childhood trauma, 4) where you live, since urban dwellers have a higher rate of schizophrenia.
Scientists liken a teen's brain to his or her messy bedroom. It's a tangled jumble of circuits and it needs to go through a streamlining process to work more efficiently - a process called 'neural pruning'. Scientists believe any substance, like marijuana, that interferes with that untangling of the brain can produce long-lasting and potentially devastating psychological effects.
Dr. Jim Van O's research shows that, "If you use marijuana regularly, your chances of becoming schizophrenic are twice as great as someone who does not smoke marijuana. If you use marijuana before the age of 16, you are four times as likely to become schizophrenic."
One question facing researchers is the 'chicken & egg' scenario: is it possible that marijuana use could be an attempt to ease the earliest or 'prodromal' symptoms of mental illness? The weight of evidence suggests that marijuana use precedes the illness, but selfmedication for pre-existing mental instability is part of the research considerations.
What if there was a simple genetic test that could tell us exactly which kids are at risk for marijuana-induced psychosis? There may be one soon. A gene called COMT, discovered in 2002, regulates dopamine levels. There are two variants of COMT, and your susceptibility to marijuana-induced psychosis depends on which combination of variants you have.
Another, little-known ingredient in marijuana could actually reduce pot's psychotic tendencies. In the 1960s, marijuana not only had less THC but more of a chemical known to actually buffer psychotic effects. That ingredient, cannabidiol (or CBD), has been effectively bred out of today's high-octane pot. In creating strains of marijuana with higher THC levels, pot growers have engineered a drug that delivers a double whammy - more psychotic-producing THC and less protective CBD.
Cannabidiol was first discovered in the 1930s, but it wasn't until the 1970s that studies showed it could reduce convulsions in rats. Recent research suggests that cannabidiol could eventually be used to treat schizophrenia. So the "pot paradox" is that the plant contains both a substance that can trigger psychosis, and another substance that could treat it.
A final thought from Dr. Robin Murray: "The problem with cannabis is that you have those on the one hand that say it's a sacred herb, and on the other extreme you have people that say cannabis is the work of the devil. But neither of these extremes is practical. What we need is a situation where people know that if you smoke cannabis heavily, particularly if you smoke the potent brands of cannabis, then you're more likely to go psychotic."
Facts about Marijuana
Marijuana is the most widely used illegal drug in the world.
- UN Drug Report, 2009
More than 31 million North Americans use marijuana at least once a year. That's about 10% of the population between the ages of 15 and 64. The comparable figure for Europe is only 5.2%.
-UN Drug Report, 2009
The highest level of marijuana use in Canada is in British Columbia, at 16.8% of the population over the age of 15. That compares with a Canadian average of 14.1%.
-UN Drug Report, 2009
The psychoactive ingredient in the cannabis plant is Tetrahydrocannabinol, or THC. Health Canada found an average THC level of 4.8% in marijuana confiscated in 1988, and an average level of 11.1% in 2008.
-RCMP
One in a hundred people will become schizophrenic in their lifetime. There are over 230,000 people in Canada with schizophrenia.
- Schizophrenia in Canada: a National Report (Schizophrenia Society of Canada)
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