(Oct. 2, 2018) The association between the use of cannabis, commonly known as marijuana, and serious mental illness is controversial. The controversy transcends multiple related concerns, including marijuana's applicability as a therapeutic drug and the causal link between marijuana use and developing psychosis. This week's research blog is the first in a two-part series regarding cannabis and serious mental illness, focusing on the questions around medical marijuana for individuals with serious mental illness.
Medical marijuana is prescribed to individuals with serious mental illness for a variety of reasons, including alternatives for pain management and to reduce symptoms of psychosis. However, heavy marijuana use among individuals with schizophrenia has been shown to significantly worsen psychiatric symptoms such as increasing the severity of psychosis episodes and altering the illness course. In addition, a recent study from RTI International found that states with more liberal medical marijuana laws had a higher prevalence of serious mental illness than those without medical marijuana laws.
In 33 states and the District of Columbia, legal barriers to or penalties for using marijuana have either been reduced or effectively eliminated. This reality has sped up the timeline on the need for findings of conclusory research about the effects of cannabis use in schizophrenia.
Mary Brunette, MD, and colleagues from the Department of Psychiatry, Giesel School of Medicine at Dartmouth Hitchcock, published an open forum piece in this month's Psychiatric Services on the impact of medical marijuana use for individuals with serious mental illness. The authors argue that with the substantial increase of medical marijuana use in this country, caution should be taken by clinicians to reduce the harm and adverse effects of medical marijuana on individuals with serious mental illness.
Part of the controversy of the effects of cannabis on schizophrenia is due to the differing effects of the two major active compounds in the drug. Tetrahydrocannabinol (THC) has addictive properties, promotes euphoria and can give rise to anxiety or paranoia. Cannabidiol (CBD) has been found to reduce psychotic symptoms and is thought to have no addictive properties. Although the links between THC and the increased risk of psychosis is clear, the debate around CBD being helpful to people with serious mental illness is still in question.
Medical marijuana programs also utilize for-profit companies to grow, create and sell these products with little regulation over their contents and safety, according to the authors. Therefore, the actual amounts and ratios of THC to CBD, vital for the therapeutic properties of the drug, may not be accurate to the label.
The authors conclude that due to the significant adverse effects of cannabis use on individuals with serious mental illness, which include worsening psychiatric symptoms and a greater likelihood of addiction to the drug, clinicians should use caution in prescribing medical marijuana among this vulnerable population.
Stay tuned next week for part two of this series regarding the causal link between cannabis and schizophrenia.
Elizabeth Sinclair
Director of Research
References:
- Brunette, M. F. et al. (2018, September). Important questions about the impact of medical marijuana on people with serious mental illness. Psychiatric Services.
- Dutra, L. M. et al. (2018, April). Medical cannabis legalization and state-level prevalence of serious mental illness in the National Survey on Drug Use and Health 2008-2015. International Review of Psychiatry.