REVIEW OF: Bolsoni LI et al, Psychopharmacology (Berl) 2022;239(5):1499–1507

STUDY TYPE: Randomized double-blind, placebo-controlled trial

Marijuana contains close to 100 cannabinoids. Among them, tetrahydrocannabinol (THC) is responsible for marijuana’s psychotogenic and rewarding effects, while cannabidiol (CBD) has some evidence to reduce psychosis and anxiety. Patients often take CBD as an oral supplement (CBD oil or gummies), and it is available as a prescription (Epidiolex) for rare forms of epilepsy. This study aimed to see if CBD can soothe symptoms of PTSD and disrupt memory consolidation of the trauma.

The double-blind trial randomized 33 subjects with PTSD to take either CBD or placebo while undergoing exposure exercises related to past trauma. Patients with a history of substance use or psychiatric disorders other than anxiety and depression were excluded. There were three total exposure sessions, each given one week apart. 

During the exposure, the subjects listened to a 90-second recording of their traumatic experience and then imagined the trauma for 30 seconds (they recorded the 90-second narrative during the first session). The treatment was only given in the second exposure session, where subjects received either CBD 300 mg or placebo before undergoing the exposure. The intent was to test whether CBD could reduce PTSD symptoms after the exposure and whether the benefits, if any, persisted over the next week.

Symptoms were measured before and after the exposure. The primary outcome was change on a visual-analogue scale of anxiety, sedation, cognitive impairment, and discomfort. Secondary outcomes included the State-Trait Anxiety Inventory, a self-reported PTSD scale, and physiologic measures of blood pressure, heart rate, and salivary cortisol.

Those who took CBD reported improvement in cognitive symptoms (feeling capable, perceptive, better able to reason, physically agile, clear-headed, sociable, and resilient), and the effects were sustained for the week after taking it. However, it did not help with anxiety, alertness, or discomfort after recall of the trauma. There were no significant changes in blood pressure, heart rate, or salivary cortisol.

The main limitation here is the fact that the researchers used multiple tests without correcting for multiple comparisons. The sample size was also small, and comorbidities were not distributed evenly between the groups despite randomization. 

CARLAT TAKE

The study provides some reassurance that CBD oil does not worsen and may improve PTSD, but the methodological flaws mean we’re not ready to endorse its use.