Headache and migraine ratings were reduced by approximately 50% after use of medical cannabis, and these reductions were greater in men compared with women, according to study results published in The Journal of Pain. Although there was evidence for the development of tolerance to cannabis’s effects on headache, there was no evidence for medication overuse headache.
Even though cannabis is commonly used to alleviate headache and migraine, sparse research exists on its effectiveness. The current study was designed to evaluate if cannabis inhalation decreases ratings for migraine and headache and to assess how sex, cannabis type (flower vs concentrate), cannabidiol (CBD), tetrahydrocannabinol (THC), or dose may contribute to these changes and to any evidence of tolerance to effects. Investigators obtained study data from Strainprint™, a medical cannabis mobile application allowing patients to track symptoms before and after use of different cannabis strains and doses. They used models to analyze data from 12,293 sessions of 1306 medical cannabis users tracking headache treatment and from 7441 sessions of 653 medical cannabis users tracking migraine treatment.
When researchers examined changes by sex, men reported significantly more sessions with headache reduction compared with women (90.9% vs 89.1%, respectively; χ2(1)=10.87; P =.001). Also, women reported significantly more sessions with headache exacerbation (ie, worsening symptoms) compared with men (2.9% vs 1.8%, respectively; χ2(1)=16.28; P <.001). Researchers did not determine any sex differences for the percentage of sessions with no change in severity of headache (women, 8.1% vs men, 7.4%; χ2(1)=2.03; P =.15). For migraines, they observed no significant differences between men and women in symptom reduction (87.3% vs 88.6%, respectively; χ2(1)=2.47, P =.12) or exacerbation (2.9% vs 3.2%, respectively; χ2(1)=0.62; P =.43), but significantly more men reported no change in migraine severity (9.9% vs 8.2%, respectively; χ2(1)=5.5; P =.02).
The use of a concentrate was associated with greater reductions in headache ratings compared with the use of flower (β=−0.09±02; P <.001), and there were no main effects in any of the models associated with CBD concentration, THC concentration, or dose. Investigators found evidence of tolerance, indicated by later headache episodes associated with a lesser symptom decrease compared with earlier episodes (β=0.13±0.05; P =.01).
Despite the study limitations, which included possible sampling bias and the lack of a placebo control group, the study investigators concluded that medical cannabis can reduce migraine and headache ratings by approximately 50%. Although evidence shows that regular use may produce tolerance, “cannabis does not lead to the medication overuse headache that is associated with other conventional treatments, meaning that use of cannabis does not make headaches or migraines worse over time. Future double-blind, placebo controlled clinical trials are warranted and will help to rule out placebo effects and provide a more controlled examination of dose, type of cannabis, THC, CBD, and THC × CBD interactions.”
Cuttler C, Spradlin A, Cleveland MJ, Craft RM. Short- and long-term effects of cannabis on headache and migraine [published online November 9, 2019]. J Pain. doi:10.1016/j.jpain.2019.11.001