Using cannabis for relief from migraine headache may be associated with developing "rebound" headache, or medication overuse headache, which occurs when pain medication is overused by patients who have an underlying primary headache disorder such as migraine, according to a preliminary study released today March 1, 2021, that will be presented at the American Academy of Neurology's 73rd Annual Meeting being held virtually April 17 to 22, 2021.

"Many people with chronic migraine are already self-medicating with cannabis, and there is some evidence that cannabis can help treat other types of chronic pain," said study author Niushen Zhang, M.D., of Stanford University School of Medicine in Stanford, Calif., and a member of the American Academy of Neurology. "However, we found that people who were using cannabis had significantly increased odds of also having medication overuse headache, or rebound headache, compared to people who were not using cannabis."

For the study, researchers looked at the records of 368 people who had chronic migraine for at least a year. Chronic migraine is defined as 15 or more headache days per month. A total of 150 of the people were using cannabis and 218 were not. The researchers looked at who had medication overuse headache and other factors that could affect the development of overuse headache, such as frequency of migraines, overuse of other medications for acute migraine and how long they had chronic migraine.

Of the 368 people, 212 had medication overuse headache and 156 did not. The researchers found that the people using cannabis were six times more likely to have medication overuse headache than those who did not use cannabis. People who were using opioids were also more likely to have current cannabis use. Previous research has shown that opioids and cannabis can both influence the part of the brain called the periaqueductal gray, which has been linked to migraine.

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