Cluster headaches

Cluster headaches: improving access to effective treatments

A 2-minute animated video
about cluster headaches

Policy paper,
November 2020:


  • About cluster headaches
  • Current medical options
  • Alternative treatments with strong evidence for effectiveness
  • The ethical need to remove legal obstacles to access
  • OPIS strategy, advocacy tools and campaigns
  • References and resources


About cluster headaches

Cluster headaches, sometimes referred to as Horton's syndrome and informally as suicide headaches, are a form of trigeminal autonomic cephalalgia and have been recognised as one of the most excruciating pains known to medicine. Unilateral and centred on one eye, the agony they cause is often compared to having a red hot ice pick driven though the eye into the brain, and sufferers are reported to have suicide rates about 20x the average. The colloquial term "headache" strongly misrepresents the extreme severity of the condition.

Attacks typically last one hour, with a usual range from 15 minutes to 3 hours, and they can repeat from once every second day to several times a day, even as often as 8-10 times in a day. Patients are often woken up several times during the night by attacks, and they go to extremes, including banging their head against the wall and punching their head, to try to distract themselves from the severe pain. About 85% of patients have episodic clusters lasting 1-3 months, occurring once or twice a year at the same time of year, during which they have daily recurrences at the frequency mentioned; the other 15% have chronic clusters that can last for years, often with multiple attacks per day and without a single day's break. Cluster headaches affect about 0.1% of the total population at some point, though one review puts the figure at 0.2-0.3%, meaning that approximately 8-20 million people globally will suffer from cluster headaches. 


Current medical options

Current medical treatments to prevent and abort cluster headaches include prescription drugs, high-flow oxygen and electrical stimulation of the vagus nerve, and they can all bring relief. However, no treatment is universally effective. For example:

  • Verapamil, used to prevent attacks, is only moderately effective, and it can have cardiovascular side effects.
  • Prednisone can be very effective in preventing attacks, even more so than Verapamil, but because of the serious side effects of taking oral steroids, it is usually only prescribed for about two weeks at a time, and attacks typically recur once it is stopped.
  • Sumatriptan is one of the most rapid-acting and effective means to abort attacks when injected under the skin, but it doesn't always reduce the pain sufficiently, and as it can also have cardiovascular side effects, there are limits to how frequently it can be used (typically just twice a day), and therefore not every attack can be safely treated. Furthermore, the more frequently a medication is taken to abort attacks, the more likely it is that "rebound" attacks will occur.
  • High-flow oxygen delivered through a non-rebreather mask can be highly effective and is safe, though it can take 15 minutes until it works, not all patients respond, and having an oxygen delivery device constantly available presents logistical constraints.
  • A recently approved antibody-based drug, Emgality, offers a new means to significantly reduce the frequency of attacks in many patients, though it does not abort them.

Some of these treatments are costly and may therefore not be available to all patients, especially if not covered by health insurance. In addition to the limits to current therapies, cluster headaches are typically misdiagnosed, and it can be several years before a patient is correctly diagnosed and prescribed appropriate treatment.


Alternative treatments with strong evidence for effectiveness

It has been observed that several drugs belonging to the indoleamine chemical family – including psilocybin (the psychoactive component of "magic mushrooms"), LSD and DMT (N,N-dimethyltryptamine, the psychoactive component of ayahuasca) – can be dramatically effective in aborting attacks and, at least for the first two (for which there is more extensive data), aborting and preventing cluster episodes, in the majority of patients. The evidence comes from a large number of anecdotes from users, desperate to find effective treatments, and more systematic studies of online fora, surveys and interviews (see reference section below). One study found that both psilocybin and LSD provided >70% of those who tried them with at least moderate protection from attacks, and complete preventative efficacy in 40% of cases – greater than that reported for any other conventional medication. Several participants reported that a single dose of psilocybin or LSD prevented attacks, shortened/aborted a cluster period, or induced remission from chronic cluster headache. According to other reports (ref 1, ref 2), inhaled DMT can abort an attack in as little as 3-5 seconds.

There are a few clinical studies currently underway with psilocybin (ref 1, ref 2) and LSD (ref) to treat cluster headaches. Aside from their efficacy, these drugs  might be safer to use than existing treatments, because of their inherent properties and because they do not need to be used as often. Indeed, a recent Phase I clinical trial on psilocybin found no adverse effects. These drugs also offer the potential to markedly reduce the cost of treatment.

Interestingly, the hallucinogenic properties of these drugs seem not to be required for their therapeutic effect: sub-hallucinogenic doses of psilocybin and LSD have been found to be effective for aborting and preventing cluster headaches in some patients, although others required larger doses. Furthermore, a non-hallucinogenic analogue of LSD, 2-bromo-LSD (BOL-148), appeared to have similar efficacy to LSD in a small-scale clinical trial. (As it is patent-protected and expensive to manufacture, it appears to be currently unavailable for use.) With DMT there is anecdotal evidence that sub-hallucinogenic doses (e.g. 3 mg) can abort attacks in some people, while in others, "breakthrough" doses of 20-30 mg may be needed.

Another related chemical with highly promising evidence for effectiveness in aborting and preventing attacks, that is only mildly hallucinogenic, and that can be legally purchased "for research purposes" in some jurisdictions, is 5-MeO-DALT. (Note that this is not the same chemical as 5-MeO-DMT, which is powerfully hallucinogenic.) There is also evidence that LSA (lysergic acid amide) can be effective, which is contained in certain commercially available seeds, though reports of side effects suggest it should be used with caution.

In addition to their usefulness for cluster headaches, there is evidence that some of the drugs mentioned here, such as psilocybin, can also be very effective in treating migraines, which of course are also highly debilitating. A clinical trial has already yielded evidence for efficacy in reducing migraine frequency.

There are additional treatments that many patients find to be effective. In particular:

  • Taurine-containing energy drinks are reported to bring relief when drunk quickly when an attack starts.
  • A specific high-dosage vitamin D3 regimen has been found to be highly effective in preventing attacks - details can be found here. (Note that vegan sources of vitamin D3 and fish-free omega-3s can be used.)

See the References and resources section below for more detailed information.


The ethical need to remove legal obstacles to access

The severe legal restrictions on the possession and use of most of these drugs complicate research and development and limit their availability to cluster headache patients. Even 5-MeO-DALT, which is only mildly hallucinogenic, has been subjected to similar restrictions in some jurisdictions. Unsurprisingly, most health services make no mention of the potential of these drugs, despite their apparent effectiveness compared to approved treatments. Increasing numbers of clinical trials on psilocybin, LSD and MDMA for the relief of post-traumatic stress disorder (PTSD) and depression, and the trend towards decriminalisation/legalisation of marijuana, are de-stigmatising the use of mind-altering substances. But such stigmas remain, and are probably a significant reason why more politicians are not yet prepared to take a strong stance to facilitate their therapeutic use.

It is nonetheless an ethical imperative that patients in severe or extreme pain be able to access and try the most effective treatments available. When governments restrict such access, compel patients to break the law and risk arrest and criminal prosecution, or impede the development of such treatments out of excessive caution, their policies are not aligned with their ethical responsibilities. Of course, as is the case with access to opioids, a balanced approach is necessary to prevent abuse, and care must be taken to ensure that a drug does not actually cause more harm than it relieves. However, in the case of cluster headaches, there is currently no such balance, and the restrictions in place allow extreme suffering to persist that could, in fact, be prevented.

OPIS advocates that people suffering from cluster headaches should be able to access the most effective treatments known.


OPIS strategy, advocacy tools and campaigns

Our approach includes:

  • Raising awareness among physicians worldwide to help reduce time to diagnosis
  • Communicating about cluster headaches and evidence for effective treatments
  • Providing useful information to patients worldwide
  • Advocating for changes in legislation to reduce legal barriers to accessing effective treatments
  • Supporting efforts to develop promising therapies


OPIS publications and videos:

We have been communicating the policy paper and video to politicians, advocacy groups, neurological associations and experts, with the goal of improving medical access to psilocybin and related substances, and ensuring that cluster headache patients can legally acquire and use these substances for therapeutic purposes.

OPIS is collaborating with several cluster headache patient organisations and groups, including Clusterbusters, Cluster Headache CommunityFinnish Horton Association, Nobism and Australia New Zealand Cluster Headache Support. We also collaborate with the International Drug Policy Consortium (IDPC), the UK-based nonpartisan advocacy organisation Conservative Drug Policy Reform Group (CDPRG), International Doctors for Healthier Drug Policies (IDHDP) and TheraPsil.

Please contact us if you would like to collaborate or support our efforts in any way, or let us know if you found any of this information helpful. We are grateful for donations to support our advocacy work.


Important note and disclaimer: The information supplied here does not constitute medical advice. We are not encouraging anyone to contravene the law within their jurisdiction. We strongly encourage anyone contemplating use of any potential therapies mentioned here to make informed decisions and to educate themselves. In particular, inhaling DMT, especially in doses >5 mg, can raise blood pressure and lead to powerful experiences that could be traumatic to the uninitiated. It is especially important to be accompanied by someone trusted, and not to wait until the onset of a cluster headache for any trials.


References and resources

General information about cluster headaches


Support and advocacy organisations and communities
  • Clusterbusters, a US-based patient advocacy and support group that provides resources, including a page on various treatment options and a page with detailed information on aborting attacks by "busting" with psychedelics
  • Cluster Headache Community, a friendly and supportive Facebook group that also provides a collection of files with information on various treatment options
  • r/clusterheads, a reddit community for cluster headache sufferers
  • OUCH - Organisation for the Understanding of Cluster Headache, a helpful UK-based support group that, however, does not openly advocate for the development of the drugs mentioned here
  • Nobism, an initiative to allow cluster headache patients to collect data on their cluster headaches through an app and have it analysed, to better determine which treatments work for them


Academic papers, talks and posters about the use of psychedelics to treat cluster headaches


Articles and posts about the use of psychedelics to treat cluster headaches


Additional resources
  • Erowid, a website providing detailed information on psychoactive substances
  • 5-MeO-DALT:
    • Legal status; see also Wikipedia page
    • Purchase: 5-MeO-DALT can be legally purchased in many countries, and it is commercially available, such as from this company that ships internationally (except US, UK and Austria), though it is sold only as a research chemical and not for human consumption.
  • How to Find Psychedelic Mushrooms, an article on the website of The Third Wave that provides some guidance to obtaining psilocybin mushrooms such as Psilocybe cubensis in jurisdictions where they have been decriminalised.
  • Information on mushrooms intended especially for people based in the UK


Please support us!

We rely on private donations to run our projects, including working to improve access to effective medication for people suffering from cluster headaches. You support is greatly appreciated!


Last updated 25 February 2021

Credit: Photo "Hell" by VasenkaPhotography used under CC BY 2.0 license

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