Marijuana shows promise in alleviating symptoms from migraine headaches. Credit: Getty Images

From chronic anxiety to seizures, there's a laundry list of ailments medical marijuana is suspected to alleviate. You can add migraine headaches to that list. A new study from the University of Colorado found that marijuana had a significant impact in either preventing or getting rid of migraines in 121 migraine patients at two Colorado dispensaries studied over a four-year period.

The patients, who smoked, used vaporizers, or ate marijuana edibles reported that their migraines decreased from 10.4 to 4.6 per month. In all, 103 said they experienced fewer migraines — that is, 85 percent of the participants. Nearly 40 percent said they experienced positive results by preventing migraines altogether or nipping them in the bud when they started. Inhaled forms were most effective in treating acute migraine symptoms, and edibles resulted in the most side effects, including drowsiness, subjects said. People who used edibles also reported that they had trouble controlling the intensity and timing of effects, as edibles kick in more slowly than other forms. 

The authors readily admit that the study has many limitations, not least of all that it isn't yet completely understood what triggers migraines in the first place. Although the cannabinoids in marijuana are thought to have pain-relieving and anti-inflammatory properties, the researchers weren't able to determine how marijuana might be affecting migraines, although they suspect that its effects on serotonin in the central nervous system could play a role. 

In addition to a lack of understanding about their causes, migraine headaches vary widely in type and in symptoms, says study co-author Laura Borgelt, a professor at the University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences. Nor did researchers note how much marijuana each patient used when they reported fewer migraines, what types or strains they used, or what the content was in terms of cannabinoids (the pain-relieving chemicals) vs. tetrahydrocannabinol (THC, the chemical that gets you high).

Still, the findings offer the possibility of relief for the 14 million people in the U.S. who suffer migraines almost daily. "Hopefully this study will put this treatment back in the hands of patients and headache specialists who were deprived of it for too long by politics," says Dr. Sunil Kumar Aggarwal, a palliative medicine physician at MultiCare Health System Adult Palliative Medicine Services.