To perform a retrospective cohort study describing Cannabidiol (CBD) use in a concussion clinic.

People report using CBD for a range of symptoms, many of which overlap with post-concussion symptoms. CBD use has not been assessed in a concussed population. We performed a retrospective cohort study to describe CBD use in a concussion clinic. We hypothesized CBD use would be more likely in patients with psychiatric diagnoses, headaches, cannabis use, and greater post-concussion symptoms and concussion chronicity. We assessed whether cannabis use could account for any of the findings.   

We reviewed medical notes from 567 selected patients aged >=18 from 07/26/2018 to 07/27/2021 and extracted self-reported CBD use and demographics, medical history, and post-concussion symptoms (via Graded Symptom Checklist (GSC)). We used descriptive and non-parametric statistics to test our hypotheses.

CBD users made up 11% of the cohort and did not differ on demographic variables (e.g., age, sex, injury acuity) from non-users. After adjusting for age, sex, injury acuity, and cannabis use, CBD users had a 3.48 (1.80, 6.75) (p < 0.001) and 1.99 (1.04, 3.99) (p = 0.04) times higher odds of reporting cannabis use and a psychiatric diagnosis, respectively, but no difference in headaches (p = 0.61). CBD users relative to non-users reported greater total post-concussion symptoms (CBD users GSC = 58.59, Non-users GSC = 45.73, p = 0.04), which was driven by cognitive (p=0.03) and physical (p=0.05) symptoms. Despite the correlation between cannabis and CBD use, cannabis use did not correlate with greater post-concussion symptoms. 

This study is the first to describe CBD use in concussed patients. CBD use was more common in concussed patients with premorbid psychiatric diagnoses and greater post-concussive symptoms, and this was not influenced by cannabis use. Prospective studies are necessary to assess the safety and efficacy of CBD in concussion.