Is marijuana really a cure for migraine?
By now you’ve probably read that sensational headline, “Medical marijuana: New study proves pot can nix migraine headaches.” Headlines don’t often tell the whole story. In this case, a lot of important facts were left out – facts you can only discover by reading the original report. Fortunately, this study is available at no cost. You just need to know the original report title, “Effects of Medical Marijuana on Migraine Headache Frequency in an Adult Population.” A simple web search will take you right to page where you can download your very own PDF copy.1
Live human trials are prohibited by federal law. Any organization which receives federal funding can loose that funding if they conduct such trials. A group of researchers at Skaggs School of Pharmacy and Pharmaceutical Sciences in Aurora, CO decided to study the next best thing – patient records. Medical marijuana has been legal by prescription in Colorado since 2001 and was legalized for recreational use in 2014. Prior to 2014, patients were required to follow-up with their prescribing physician in order to maintain their medical marijuana cards. After full legalization, that requirement was eliminated. Enlisting the help of Gedde Whole Health, a private medical practice specializing in the treatment of state-qualified medical conditions with medical marijuana, they identified patients with a confirmed primary diagnosis of migraine and selected only those patients who participated in follow-up visits. 121 patient charts were reviewed — documenting diagnosis, frequency of migraine attacks before and after treatment, plus dose and delivery method of marijuana.
- Slightly less than half (48%) of the patients reported using prescription preventive or abortive medication either before or after treatment.
- 8% reported prior marijuana use.
- The average monthly consumption was 2.38 oz. or a little more than 2 g per day.
- Delivery methods included: vaporized, edible, topical, and smoked.
- Most patients reported daily use as a preventive.
- 11% also reported using vaporized marijuana as an acute abortive.
- 85.1% of subjects experienced a significant reduction in migraine headache frequency.
- Prior to treatment, these patients averaged 10.4 attacks per month.
- At follow-up appointments, these same patients reported an average of 4.6 attacks per month.
Most clinical trials are considered successful if ≥50% of subjects experience a ≥50% reduction in frequency and/or severity of symptoms. With 85.1% experiencing a 52.6% improvement in migraine frequency, results are on par with some of the most successful pharmaceutical preventives.
Positive effects reported:
Adverse effects* reported:
- difficulty controlling effects due to timing & dose
- increased headache
- bad dreams
- memory loss
*Patients using edibles were more likely to report negative effects.
This is the first study to demonstrate that marijuana use reduces the frequency and severity of migraine headache. The results are, admittedly, promising. But before you get too excited, remember that this study was a retrospective chart review. By design, it contained several major weaknesses.
Even the research team acknowledged several limitations:
- The results do not prove that marijuana was the definite cause of reduction in migraine attack frequency.
- Chart documentation was inconsistent from patient to patient
- Most patients reported previous use of marijuana prior to their first visit.
- There was no distinction between prior medicinal or recreational use.
- The study could not allow for controlling the type of dose used.
- Doses varied from less than 1 to over 2 ounces per month.
- Daily doses were not standardized and were prepared and administered in patient homes.
- There was no documentation in patient charts of specific instructions on preparation or dosing.
- There was no documentation of dosing frequency or strain used.
They recommend the following for further studies:
- Randomized, placebo-controlled clinical human trial
- Marijuana washout period prior to start of trial
- Standardized quantities and potencies of medical marijuana
- Tracking of patient adherence to dosing instructions
- Tracking of migraine headache frequency
- Tracking of adverse effects
They readily admit that federal laws will have to change dramatically in order to make such as study possible.
There were other weaknesses to this study not mentioned by the researchers. As with the ones they mentioned, only changes in legislation will make it possible to design a study without these weaknesses.
Most glaringly, records did not indicate whether or not patients had been diagnosed by a true headache specialist according to the ICHD. All patients had already received the diagnosis of “migraine” without specifying if it was Migraine with Aura, Migraine without Aura, Hemiplegic Migraine, Chronic Migraine, or any other migraine diagnosis. It is possible that some patients were incorrectly diagnosed. Future studies should be designed so that subjects’ diagnoses are confirmed by a headache specialist using the diagnostic criteria in the ICHD. Future studies should isolate subject groups by diagnosis or enroll only patients with a single diagnosis for more accurate results.
Another weakness I observed was that there wasn’t a lot of information regarding the impact marijuana use had on other migraine symptoms. By relying on chart review, the team could only report what was in the charts. Some patients reported that marijuana use reduced the symptom of nausea, but none reported an impact on light or sound sensitivity. Most of us agree that migraine is a lot more than just a headache. So it would be nice to know if treating migraine with marijuana will reduce all the symptoms of migraine, not just the headache. Future studies should include subject education on the tracking of all symptoms to ensure that this information is part of the results.
Timing of follow-up
Lastly, not all patients were required to follow up with the prescribing physician. The time between initial and follow-up appointments was 1 to 3 years. We all know that migraine frequency can vary from time to time. The follow-up time is simply too long to rule out other factors that may have influenced migraine attack frequency. In clinical trials, patients are usually asked to follow up every few weeks, a month at most.
A girl can dream
Like many of you, I’m in favor of ending marijuana prohibition so that it can be properly studied for its medical effectiveness. It has a long history of use for a variety of medical problems. I’d really like to see some definitive proof that doctors throughout history have been on the right side of this debate.
Alas, I live in a state that is unlikely to legalize marijuana any time soon. Darn.