Juan Esteban Perez, MD

 

Tags:  Medical cannabis; psychiatry; anxiety; depression; ADHD; PTSD; Tourette’s; CBD; THC

 

The problem: Cannabinoids such as tetrahydrocannabinol (THC) or cannabidiol (CBD) have been associated with a potential therapeutic role in the treatment of various medical conditions, especially in certain psychiatric conditions such as anxiety, depression, attention deficit and hyperactivity disorder (ADHD). In fact, mental disorders are the second leading cause of medicinal cannabis prescriptions. However, evidence in this matter is highly inconsistent, and there are no clear recommendations or guidelines published yet. 

 

Why do this study? This study analyzed available literature regarding the use of cannabinoids in the treatment of common psychiatric conditions, in order to evaluate the quality of this evidence and provide improved recommendations for care. A secondary goal was to identify gaps in the literature in order to direct future studies.

 

The study: A thorough literature review was performed, searching for evidence regarding the use of cannabinoids (natural/synthetic) for the treatment of depression, anxiety, ADHD, Tourette’s syndrome, post-traumatic stress disorder (PTSD) and psychosis. A total of 83 studies were included for analysis, of which 50 were randomized controlled trials. 

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Studies were grouped and analyzed by each specific mental disorder endpoints of disease remission (complete resolution of symptoms), or improvement in symptom severity or frequency. Secondary outcomes for all conditions included measures of global functioning, perceived improvement by patient or caregiver, and adverse effects. The quality of the evidence was also assessed using the Grading of Recommendations, Assesment, Development and Evaluation (GRADE) methodology, and categorized evidence into “high quality”, “moderate quality”, “low quality” or “very low quality.

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The results of this analysis are inconclusive for the most part, and most of the evidence examined was graded either low or very low. This study found that there is no evidence that favors the use of medicinal cannabis for depression, ADHD, Tourette's Syndrome, PTSD or Psychosis. A significant association was found regarding a decrease in anxiety symptoms in the setting of chronic disease, but not when anxiety was the primary diagnosis.

 

Conclusions:  The main conclusion drawn from this exhaustive study is that there is a lack of high-quality data regarding the use of medicinal cannabis for the treatment of mental disorders.

 

What does this study add? The use of medicinal cannabis is a highly debated and controversial topic. This study aimed at examining the evidence regarding cannabinoid prescription and use for a variety of mental disorders. Even though mental disorders are the second most common cause for cannabis prescriptions, there was a surprising lack of good quality evidence to generate a clear recommendation either favoring or opposing the use of cannabis. This study highlights the fact that there is a dire need for the development of high-quality research protocols, in order to properly define the role that cannabis has as a treatment option for mental disorders. 

 

Funder:  Therapeutic Goods Administration, Australia; Commonwealth Department of Health, Australia; Australian National Health and Medical Research Council; and US National Institutes of Health.

 

Author conflicts:  MF and LD have been investigators on independent, investigator-driven educational grants funded by Reckitt Benckiser, Mundipharma, and Seqirus. MF, GC, and LD have been investigators on independent investigator-driven educational grants funded by Indivior. All other authors declare no competing interests.

 

Commentary: (David Casarett MD)

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Great.  Just what the field needs:  yet another study that declares that more research is needed.  That result isn’t surprising, given the state of cannabis research, but it’s still disappointing.  Especially since millions of people use cannabis for these conditions.  Come on, people.  Let’s help cannabis research catch up to what patients are doing every day.