Migraine attacks can be lessened by medical marijuana, according to a new study conducted by researchers from the Skaggs School of Pharmacy and Pharmaceutical Sciences at the University of Colorado Anschutz Medical Campus.

The researchers analyzed the charts of 121 patients who were diagnosed with migraine and treated at a medical marijuana specialty clinic called Gedde Whole Health. More than 60 percent of the patients were taking or had a history of taking marijuana when their treatment began. The treatment period lasted from January 2010 to September 2014.

Based on the patients' records, treatment with medical cannabis reduced migrane attacks from 10.4 to 4.6 in a month. Among the patients, 103 said the frequency of their migraines decreased, while 15 said the frequency of their migraines remained the same. Only three said the attacks increased.

These numbers, according to the researchers, are statistically and clinically significant. This is the first study to show reduced migraine frequency after medical marijuana treatment.

"There was a substantial improvement for patients in their ability to function and feel better," lead study author Laura Borgelt said in a press release. "Like any drug, marijuana has potential benefits and potential risks. It's important for people to be aware that using medical marijuana can also have adverse effects."

Borgelt explained that cannabinoid receptors in the body could affect serotonin, a neurotransmitter, which she believes "plays a role in migraine headaches." However, she said the research team is still studying "the exact role of cannabinoids" in treating migraine.

Although the results showed that medical marijuana treatment reduced migraines, it is still unclear how exactly cannabis was able to do so. Borgelt said more studies are needed to examine this further.

"Prospective studies should be conducted to explore a cause-and-effect relationship and the use of different strains, formulations, and doses of marijuana to better understand the effects of medical marijuana on migraine headache treatment and prophylaxis," the study authors wrote.

The study was published online Jan. 9 in the journal Pharmacotherapy.