By Pat Anson, PNN Editor

Inhaled cannabis can significantly reduce both headache and migraine severity, according to a large new study that looked at patients who self-reported their symptoms. But researchers say the effectiveness of cannabis diminished over time, as patients used larger doses for pain relief and appeared to develop a tolerance to the drug.

Researchers at Washington State University analyzed data from the Strainprint app, which allows patients to track their symptoms while using medical cannabis. Data was collected from nearly 2,000 patients who used the app almost 20,000 times to track their headache and migraine pain before and after inhaling cannabis by smoking or vaping. The cannabis was obtained from licensed medical cannabis distributors in Canada.

"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 lead author Carrie Cuttler, PhD, a WSU assistant professor of psychology. "We wanted to approach this in an ecologically valid way, which is to look at actual patients using whole plant cannabis to medicate in their own homes and environments.”

The study, published online in the Journal of Pain, is the first to use data from headache and migraine sufferers using cannabis in real time. Previous studies have asked patients to recall the effect of cannabis use in the past.

Cuttler and her colleagues found that self-reported headache severity fell by 47.3 percent and migraine severity declined by 49.6 percent. Cannabis concentrates, such as cannabis oil, produced a larger reduction in headache severity than cannabis flower.

There was no evidence that cannabis caused "overuse headache," a pitfall of opioid medication and other pain relievers that can make headache pain worse over time. However, researchers did see patients using larger doses of cannabis over time, indicting they may be developing tolerance.

There was no significant difference in pain reduction among cannabis strains that were higher or lower in levels of tetrahydrocannabinol (THC) and cannabidiol (CBD). Since cannabis is made up of over 100 cannabinoids, the finding suggests that different cannabinoids or organic compounds like terpenes may play a central role in headache and migraine relief.

Cuttler acknowledged the limitations of using an app to collect data, since it relies on a self-selected group of people who may already anticipate that cannabis will work to alleviate their symptoms. It was also not possible to use a placebo control group.

"I suspect there are some slight overestimates of effectiveness," said Cuttler. "My hope is that this research will motivate researchers to take on the difficult work of conducting placebo-controlled trials. In the meantime, this at least gives medical cannabis patients and their doctors a little more information about what they might expect from using cannabis to manage these conditions."

PNN columnist Mia Maysack, who suffers from chronic migraine and cluster headache, reluctantly agreed to try cannabis after her first cluster headache lasted 54 straight days. Mia said she “almost instantaneously felt better.” Now she uses cannabis regularly.

“It helps me combat nausea, cultivate an appetite, gives a slight boost in morale, and get quality rest,” Mia wrote in a column. “Cannabis works for me about half the time.  But that goes deeper than a glass half empty or half full.  It's a matter of having a resemblance of a life or not.”