In numerous studies around the world, the use of cannabis has been shown to increase the risk for schizophrenia and 
psychosis. Researchers in New Zealand found that individuals using cannabis before the age of 15 were more than 300% more likely to develop mental illnesses like schizophrenia, while professor Robin Murray of the London Institute of Psychiatry’s 15 year study has shown that regular use of cannabis by 15 year olds resulted in people being 4.5 times more likely to become schizophrenic by the age of 26.
Almost all research has indicated that the risks for increased psychosis are higher when the drugs are used by people under the age of 21, as the brain is developing more rapidly and is more vulnerable. It’s believed that when marijuana is used while the brain is developing, the chemical dopamine is increased which can lead to schizophrenia. Biological predisposition towards schizophrenia and psychosis will also play a role in the level of risk – as Professor John Henry of Imperial College in London shows in his research.
It’s believed by the British Lung Association that the increased potency of today’s marijuana available on the streets today is 15 times more powerful than the drug that was smoked 30 years ago – and is contributing to the increased risks of psychosis and schizophrenia.
From Schizophrenia.com:
“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.”
Cannabis, or Marijuana has been a recreational drug of choice for many decades. There are many advocates pushing for legalizing medical marijuana use, and just as many enemies who want to keep marijuana use illegal. Federal laws in the United States indicate that all use of Marijuana is illegal – even if an individual state allows medical marijuana use.
Additional studies and research of 3,100 young adults around the age of 20 years old who admit to smoking pot for 3 years or more found that 65 had been diagnosed with mental illnesses and 233 have had at least one instance of hallucinations.
Most researchers agree that further study is needed in order to draw conclusions whether or not cannabis usage causes mental illness or if people who use cannabis already have a higher pre-disposition to the mental illnesses.
If the link from marijuana use to increased mental illness is proven successfully, you’ll probably start to see even stronger arguments against the use of medical marijuana.
Studies Show Marijuana May Increase Psychosis was created by and is property of American Consumer News.
