Cannabis has the potential to elicit schizophrenia in people predisposed to having it.
You're under-exaggerating it. It's a lot more than a potential, especially if you smoke it extremely young.
Of course lot's of the science is still a grey area, considering it's hard to ethically do a truly random test.
Researchers in New Zealand found that those who used cannabis by the age of 15 were more than three times (300%) more likely to develop illnesses such as schizophrenia. Other research has backed this up, showing that cannabis use increases the risk of psychosis by up to 700% for heavy users, and that the risk increases in proportion to the amount of cannabis used (smoked or consumed). Additionally, the younger a person smokes/uses cannabis, the higher the risk for schizophrenia, and the worse the schizophrenia is when the person does develop it. Research by psychiatrists in inner-city areas speak of cannabis being a factor in up to 80 percent of schizophrenia cases.
Professor John Henry, clinical toxicologist at Imperial College London said research has shown that people with a certain genetic makeup who use the drug face a ten times (1000%) higher risk of schizophrenia. (for example - if your risk of schizophrenia was 6% (due to a family history of mental illness) prior to taking cannabis, it could be 60% -- or more likely than not - after taking cannabis). Every person is different (i.e. has different genes and different environments) - so this "10 Times Higher Risk with cannabis use"- is just a generalization, and it may or may not apply to a given person.
The increased risk applies to people who inherit variants of a gene named COMT and who smoked cannabis as teenagers. About a quarter of the population have this genetic make-up and up to 15 per cent of the group are likely to develop psychotic conditions if exposed to the drug early in life. Neither the drug nor the gene raises the risk of psychosis by itself.
Without the effects of the drug, such a person might live their whole life without ever experiencing mental health problems. It has been estimated, for example, that between 8% and 13% of people that have schizophrenia today would never have developed the illness without exposure to cannabis.
Sure, 8-13% doesn't seem like a huge number, but all of those people could have easily prevented it.
Tom, do you understand what I'm trying to say? Even if you think it's wrong, is it actually hard to understand?
Yeah, and I don't completely think it's wrong.