Results of a study released in January indicate a significant decrease in the frequency of migraine headaches in a group being treated with medical marijuana.

The article, published by the National Center for Biotechnology Information, describes a preliminary investigation of outcomes of one hundred and twenty-one patients diagnosed with migraine, who were treated with medical marijuana between January, 2010 and September 2014. Patients included in the study group were selected from among adult patrons of two medical marijuana specialty clinics in Colorado.

The average frequency of headache within the group decreased from 10.4 headaches per month to 4.6 headaches per month. Additionally, 11.6% of patients reported a reduction in duration of headache.

The investigation was mounted partly in response to recent studies suggesting a relationship between headache and levels of the neurotransmitter serotonin in the brain, and evidence that cannabis may increase serotonin levels.

To our knowledge, no clinical (such as blind and placebo controlled) trials have yet been undertaken to determine what link—if any—may exist between cannabis use and the frequency and intensity of migraine episodes. The results of the Colorado study, however, support such clinical testing in an effort to verify efficacy. If such a cause-and-effect link is found, these studies should also aid in determining factors such as dosing and the possible varying effects of different strains of cannabis.