A review of current literature did not find evidence to support the use of cannabinoids for the treatment of psychiatric disorders. These findings were published in the American Journal of Psychiatry.
To assess the most current evidence about cannabinoids, the review authors searched publication databases through July 2021 and 841 articles were reviewed.
Policies regarding cannabis have been rapidly changing in the United States US and as of September 2021, 36 states and the District of Columbia (DC) had medical cannabis laws and 16 states and DC had legalized recreational cannabis use.
Cannabinoids have a Schedule I classification by the US Drug Enforcement Agency (DEA) meaning the substance has no legal definition of medicinal use and has a high risk for abuse just like heroin and LSD. In addition, the US Food and Drug Administration (FDA) has not sufficiently studied cannabis and it remains underregulated.
There are three cannabinoid products that have been approved by the FDA: dronabinol, nabilone, and cannabidiol. However, there is limited data to support the use of these products for clinical populations and these too remain underregulated.
Cannabidiol’s pharmacological properties indicate that there is the potential to have anxiolytic, antipsychotic, anticonvulsant, antioxidant, analgesic, and immunomodulatory functions.
Acute use has been associated with impaired learning, attention, memory, and motor coordination and may affect executive functioning involved in planning, organizing, solving problems, and making decisions. Some individuals who reach cannabis intoxication can experience feelings of anxiety, paranoia, and cannabis-induced psychosis.
Chronic use has been associated with increased risk for addiction, cognitive difficulties, psychiatric illness, and other systemic effects. A longitudinal study identified neurodevelopmental abnormalities of accelerated cortical thinning of the prefrontal regions of the brain, especially among individuals who began use earlier in life.
The second most common use of medical cannabis and cannabinoids, after chronic noncancer pain, is for the treatment of psychiatric disorders. Despite the relative widespread use, a recent systematic review and meta-analysis found limited evidence that cannabinoids effectively treated anxiety disorders and no evidence to support its use for other psychiatric conditions.
Multiple states have specified medical cannabis can be used for the treatment of posttraumatic stress disorder (PTSD), however there is conflicting evidence to support these policies. One study found cannabis use reduced nightmares associated with PTSD, another study found cannabis use exacerbated symptom severity, and a third study found no significant difference between users and nonusers.
Although evidence for medicinal applications of cannabinoids is developing, psychiatric clinicians are in need of evidence-based guidelines to help guide treatment plans.
The review authors stated that cannabinoid pharmacotherapy may be a reasonable third-line treatment for patients with chronic pain whose psychiatric presentation is affected by their pain and are at low risk for substance use disorder.
In general, clinicians should avoid initiating or recommending cannabinoids for most psychiatric patients as no clinical trials have supported its use.
Robust clinical trials of cannabinoids are needed, however, the DEA Schedule I classification and the lack of funding from states or pharmaceutical companies remain significant barriers to research.
Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.
Hill KP, Gold MS, Nemeroff CB, et al. Risks and benefits of cannabis and cannabinoids in psychiatry. Am J Psychiatry. 2021;appiajp202121030320. doi:10.1176/appi.ajp.2021.21030320