Cannabis consumption can cut the severity of headaches in half, according to new research from the University of Washington.

The study led by assistant professor of psychology Carrie Cutter analyzed data submitted to the Strainprint app, which allows users to track their cannabis usage and earn rewards. It helps them gauge the effectiveness of medical marijuana in treating their symptoms, allowing them to work out the best dosages and strains.

Strainprint can then use the data it harvests to provide analytics reports designed to support medical cannabis practitioners advance the scientific understanding of the effects of marijuana.

Cutter and her team found more than 1,300 patients that uploaded information about the effects of cannabis upon their headaches. They used the app more than 12,200 times to track changes in headache severity from before to after cannabis use.

A further 653 patients used the app on more than 7,400 occasions to track changes in migraine severity.

After crunching the numbers, the researchers at Washington University found that inhaled cannabis reduces self-reported headache severity by 47.3% and migraine severity by 49.6%.

The university billed it as the first time big data has been used to study marijuana’s effectiveness in treating this common medical complaint. “We were motivated to do this study because a substantial number of people say they use cannabis for headache and migraine, but surprisingly few studies had addressed the topic,” said Cutter.

She added that she was blessed with “very big data”, allowing her team to gain robust findings. The researchers saw no evidence of headaches being caused by overuse of cannabis, but they did see patients using larger doses of cannabis over time, indicating they may be developing tolerance to marijuana.

The researchers also noted that cannabis oil and concentrates produced a larger reduction in self-reported headaches than smoking cannabis. However, there was no noticeable difference between strains that were higher or lower in THC and CBD levels, which suggests that other terpenes found within cannabis might be the most effective at treating headaches and migraines.

Cutter believes some patients may have overestimated the effectiveness of marijuana on their symptoms, but she hopes that her research will spark placebo-controlled trials that offer even more robust findings.