There have been many research studies suggesting that marijuana may increase risk of schizophrenia (see here). But there is also a recent study at Harvard Medical School, led by Ashley C. Proal, that has suggested this may not be the case. This recent comparison between families with a history of schizophrenia and those without, found no connection to marijuana as a cause for the disorder.

There are over 400 different chemicals in the marijuana plant, so the issue is more complex than it might seem at first and it appears that there may be some chemicals from the plant that may actually be helpful for people who have schizophrenia.

In fact, GW Pharmaceuticals (www.gwpharm.com), which has several cannabinoid-based drugs in the research pipeline, is now gearing up for a human trial of one of its CBDs to treat schizophrenia. Steve Schultz, VP, investor relations, says the company wants to differentiate itself from medical marijuana. “We grow all our plants in a controlled environment and extract various chemicals that undergo rigorous testing. This is completely different from medical marijuana, which is not regulated.”

Studies have shown that CBDs block, or counteract the effects of THC (terahydrocannabinol) which is the psychotogenic part of cannabis, and are anti-psychotic in humans.

The company will be enrolling 80 patients in Europe this year for a Phase IIa trial that will examine the safety and efficacy of a purified CBD agent the company has titled GWP-42003. Preclinical data verified that it has anti-psychotic effects in pre-clinical models of schizophrenia, as well as demonstrating a reduction in movement disorders often induced by current anti-psychotic drugs. What sets this compound apart from current anti-psychotics is that cannabinoids do not work via the dopamine D2 receptor and may have the potential to target both positive and negative symptoms of the disease. This may, in turn, improve patient compliance.

Additional in-house research indicates that cannabinoids show potential to treat additional mental health disorders, such as: anxiety, bipolar affective disorder, depression, treating disorders, insomnia and post-traumatic stress disorder.

There have been a number of published papers on the topic of cannabinoids and Schizophrenia. Some of these are listed on the company website: www.gwpharm.com.