According to Harvard Medical School, there is mounting evidence that teens who regularly use marijuana increase their risk of developing psychosis, a severe mental disorder that causes a complete break with reality.
Marijuana also appears to increase the chances of developing schizophrenia, a long-term psychotic disorder that causes disassociation from thoughts, emotions and behaviors.
A recent study followed 2,000 young people through adolescence and early adulthood. Those who had smoked marijuana five times or more as teenagers were twice as likely to develop psychosis at some time during the next decade. Another study found that marijuana use during adolescence can hasten the onset of schizophrenia by three years.
The Genetic Connection
Teenagers who have a parent or sibling who has been affected by psychosis have a nearly one in 10 chance of developing the condition themselves. If they use marijuana on a regular basis, their risk is doubled. In comparison, teens who have no history of psychosis in their family have a less than 10 in 1,000 risk of developing it. This group of teens has a 14 in 1,000 risk of developing psychosis if they regularly smoke marijuana.
An earlier study that focused on marijuana and schizophrenia followed 50,000 Swedish soldiers over a period of 15 years. Soldiers who smoked marijuana as little as one time were more than twice as likely to develop schizophrenia. Those who smoked more than 50 times (“heavy users”) were six times more likely to develop the disorder.
These studies don’t prove that smoking marijuana causes psychosis or schizophrenia, but they do show an association. Ann MacDonald, editor of Harvard Health, compares this to the earliest discovery of an association between tobacco and lung cancer. Until further research was conducted to prove how smoking damages the lungs and leads to cancer, scientists could not say that cigarettes cause cancer. Current research related to marijuana’s effect on the brain is still at that early stage. Although scientists know that THC (one of the active ingredients in marijuana) triggers chemical reactions in the brain, they do not know why using marijuana as a teenager can increase the risk of psychosis and schizophrenia.
One thing is clear — these studies provide even more reason for teenagers to avoid marijuana. This is especially true for those who have a family history of psychotic disorders or schizophrenia. The short-term thrills provided by the drug could have very serious consequences in the long run.