Marijuana-based chemical can be useful in the treatment of schizophrenia, says Canadian study

A new study from Western University concludes that a chemical found in marijuana can be useful in the treatment of schizophrenia.

The study, led by Justine Renard, postdoctoral fellow in Western’s Department of Anatomy and Cell Biology at the Schulich School of Medicine and Dentistry, identifies the neural pathway whereby the cannabis-derived phytochemical cannabidiol (CBD) produces antipsychotic effects that are found to reduce symptoms of schizophrenia-related psychosis.

“These findings have critical implications not only for understanding how specific phytochemical components of marijuana may differentially impact neuropsychiatric phenomena, but demonstrate a potential mechanism for the therapeutic effects of marijuana derivatives in the treatment of dopamine-related, psychiatric disorders,” say the study’s authors.

Marijuana contains two main chemicals responsible for producing its psychoactive properties -the more well-known THC or tetrahydrocannabinol and CBD.

And while THC serves to produce the drug’s psychoactive properties, CBD has been found to have an opposing, antipsychotic effect, which makes it potentially ideal for use in treatment of psychoses such as schizophrenia. The link between marijuana and schizophrenia has been known for some time, as studies have shown that heavy marijuana use, particularly in adolescence, increases the risk of developing schizophrenia and that schizophrenics who use marijuana are more liable to have worsening symptoms and further progression of the illness. But recent evidence including the work done at the Western University lab points to THC as the culprit rather than CBD.

“CBD is acting in a way that is the exact opposite to what THC is doing,” says co-author Steven Laviolette. “Within the same plant, you’ve got two different chemicals that are producing opposite effects in terms of psychiatric effects, molecular signaling and effects on the dopamine pathway.”

Researchers injected rats with CBD to study its behavioural, chemical and neuropathic effects and found that it serves to reduce dopamine sensitization -a response that has been linked to schizophrenia-related psychoses. This helps to explain exactly how CBD affects brain functioning (an unknown up to this point) but it also points to a novel approach for treating psychoses, something researchers say is sorely needed.

“One of the biggest problems in treating schizophrenia is that there hasn’t been an effective new treatment on the market in a very long time,” says Laviolette. “The drugs on the market today have limited efficacy and horrible side-effects; there is a desperate need for safer alternative medications.”

While the federal Liberal government has promised to legalize and regulate the sale of marijuana in Canada, a February, 2016, study in the United States on the impacts of recent legalization of marijuana in Colorado, Washington, Oregon and Alaska finds that marijuana use has gone up among adults but that its use by youth aged 12 to 17 has not increased significantly. Other results of the study were that young people’s perceptions of the risks of using marijuana have decreased over the same time period, that the potency of marijuana has increased and that in at least one locale – Denver, Colorado – marijuana-related hospital admissions and calls to poison control centres have risen considerably.

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