March 1 (UPI) -- Cannabis may provide some relief for the symptoms of migraine, but it may be fleeting because of the potential onset of a "rebound" headache, according to an analysis released Monday by the American Academy of Neurology.
People using the drug, which has been shown to reduce the intensity of migraine symptoms, were six times more likely to experience a rebound headache than those who other treatments.
A rebound headache occurs when those with an underlying headache disorder, such as migraine, rely too heavily on a certain pain medication, the researchers said.
"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," study co-author Dr. Niushen Zhang said in a statement.
"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," said Zhang, a headache and facial pain specialist at Stanford Health Care in Palo Alto, Calif.
Zhang and her colleagues will formally present their findings during the American Academy of Neurology's 73rd Annual Meeting, to be held virtually in April.
Migraine, which affects approximately 12% of the population, is a potentially disabling severe headache that can cause significant pain, as well as sensitivity light and smell, according to the American Migraine Foundation.
Attacks sometimes increase in frequency over time and chronic migraine is defined as 15 or more headache days per month, Zhang and her colleagues said.
In areas where its use has been legalized, cannabis is often prescribed with or in place of medications such as antidepressants or beta-blockers to help control symptoms.
Research suggests that the key ingredient in marijuana can help reduce the intensity and frequency of migraine attacks.
Still, as with more conventional prescription pain relievers used for people with the condition, it can also cause rebound headaches, which have been associated with medication overuse, according to migraine foundation.
For this study, Zhang and her colleagues looked at the medical records of 368 people who had chronic migraine for at least one year. Among the study participants, 150 were using cannabis and 218 were not.
Of the 368 participants, 212 reported at least one medication overuse headache over the course of the year, while 156 did not, the researchers said.
People using opioid pain relievers to treat migraine also were more likely to use cannabis, they said.