When investigating the possibility of a connection between marijuana smoking and schizophrenia, it is immediately apparent that there are two schools of thought. One camp believes that marijuana can trigger schizophrenia in those who are predisposed to the disease due to genetics or family history. The other camp believe those with schizophrenia are at increased risk for smoking marijuana.
A study published in Molecular Psychiatry lends credence to the theory that schizophrenia plays a role in a person’s proclivity to smoke marijuana. Researchers say that although the association is not clear-cut, a small part may be due to genetic overlap when the same genes that cause people to enjoy marijuana might also predispose them to schizophrenia.
Researchers took genetic data from published schizophrenia studies and applied it to a random sample of 2,000 healthy Australians to see if the variants could predict marijuana use. Genetic psychiatrist Robert Power, lead author of the study at King’s College, London, said there is a well established connection between people using marijuana and schizophrenia. The study indicated those at risk for schizophrenia were more likely to use marijuana and in greater amounts.
The chicken and the egg – conflicting views
However, Eden Evins, a psychiatry professor at Harvard University who was not involved in the study, called the findings “valuable” but maintains that they don’t rule out previous findings that marijuana use increases a person’s risk for developing schizophrenia, saying “both may be true.” Wolfram Kawohl, a psychiatrist at the University of Zurich feels that both connections may exist parallel along with possible others.
Lynn De Lisi, another Harvard University professor, points to her own work, which showed no difference in genetics between marijuana smokers and nonsmokers. De Lisi believes there should be studies of people using marijuana compared with those who don’t, each having a family history of schizophrenia. She doesn’t think everyone smoking marijuana today has the genetic predisposition to do so.
Marijuana affects people with schizophrenia differently
Matthew Hill, a cell biologist at the University of Calgary in Canada, cites studies that have demonstrated marijuana having a very different effect on the brains of people with schizophrenia compared to healthy people. The release of dopamine triggered by marijuana smoking is magnified in the brain of a person with schizophrenia, resulting in a chronic dopamine elevation level that increases the chance of a psychotic episode.
Since no single gene has been identified to associate with addiction or schizophrenia, the illnesses are the result of multiple genes working in combination. Evins said, “There’s also a plethora of environmental factors that need to be taken into account, most of which we barely understand.”
Approximately 1 percent of the population has schizophrenia, so the majority of adolescents who use marijuana will not develop the disorder. There is no explanation for the fact that schizophrenia rates remain stable while marijuana use is increasing.
Because researchers and clinicians cannot agree on a definitive link between marijuana and schizophrenia, or even the order of appearance, more studies are needed to reveal new information.
When patients with schizophrenia abuse marijuana, both conditions must be treated concurrently. Sovereign Health provides effective dual diagnosis treatment to address co-occurring addictions and mental illnesses. If you would like further information, please call our 24/7 helpline
Written by Veronica McNamara, Sovereign Health Group writer