Anat[i], an executive at a medical start-up company, experiences migraine headaches 3-4 times per month. She believes that her headaches are triggered by eating foods with monosodium glutamate, drinking wine, and eating chocolate, so she tried to minimize these in her diet. However, Anat also notices that she sometimes gets a migraine the day after a late night. Recently, she had eaten hamburgers at a barbeque the day of her migraine, so she is now concerned that hamburgers may be a trigger – and she really does not want to avoid hamburgers. Anat wants to know what really triggers her headaches.
Most migraine sufferers have things that they think bring on their migraines
A recent review of many research studies that reported on migraine triggers concluded that a majority of people with migraine think they know what triggers their episodes and also that they can predict when a migraine will occur based on certain warning signs, otherwise known as premonitory symptoms[ii]. While the frequency of reported triggers varies from study to study, the common triggers can be categorized as:
- Physical: Stress, strenuous exercise
- Hormonal: Pre-menstrual, menstrual
- General health: Sleep deprivation, fasting, missing meals, dehydration
- Food: alcohol, chocolate, hard cheese, Chinese food
- Other: Weather changes, perfume
What’s the difference between a ‘cause’, a ‘trigger’, and a ‘premonitory symptom’?
Many people report factors that may be associated with a headache with words that may be confusing: cause, trigger, and premonitory signs. To keep it straight:
- A ‘cause’ is the real reason for the headache, and it is best reserved for the scientific mechanisms that underlie the migraine phenomena. An individual suffering from migraine usually has no way of knowing the true cause of the headaches. We also use the word ‘cause’ in a broader sense to indicate a factor that has a strong connection with a result. So, if drinking beer always (or almost always) resulted in a migraine, then we could conclude that it is a cause of the migraine. We usually do not have that level of certainty.
- A ‘trigger’ is some real-world factor or circumstance that can predispose a migraine sufferer for a new migraine episode. You think they know about their triggers after observing that migraine episodes occurred in association with certain factors.
- A ‘premonitory symptom’ is some feeling that is not specific to migraine, but that you think commonly comes hours or days before your migraine episodes. Premonitory symptoms are generally thought of as warning signs that could predict a migraine.
Why is it important to find out about my triggers and warning signs?
Of course, it would be great to prevent the migraine from coming. For one thing, if you know that you are at high risk for a migraine, you could be extra-careful to avoid the triggers that predispose you to an attack. Also, you may be careful to limit your risk of migraine episodes by avoiding multiple triggers at once. Certainly, you may also be diligent about taking your migraine medications with you if you know that there is a good chance that you will be getting a migraine.
How can I tell if certain foods really trigger migraine?
It is actually very hard to tell. Since you eat many types of food it could be hard to decide which food is the culprit. Also, it may not be the food, at all. Was it the hamburger, the ketchup, the fries, or none of the above? To make matters worse, you may be biased by what your friend thinks triggers her headaches. According to behavioral psychologists, we are not very good at figuring out causative relationships since there are always many possible interpretations of our observations, and we tend to favor interpretations that support our favorite theories (“Confirmation bias”)[iii]. So, if you already have in your mind that saccharine triggers your migraine, then you are likely to blame the diet soda rather than the Chinese food or the beer.
Solution: Collect and analyze data about your personal triggers
Scientists conduct prospective experiments to establish causative relationships. They systematically vary the suspected trigger while keeping other factors under control. It would be great if you could do that. However, in the real world the conditions are not controlled and there are lots of factors that may contribute to a migraine. So, what can be done?
Empowering patients with better data about their triggers
The best way to make meaningful connections between real-world factors is to scientifically observe and analyze a lot of data from the days preceding migraine episodes. While this was not practical before the advent of smartphones, it can now be done in an easy and effective way. I am leading a large project to log and analyze personal migraine experiences using a new smartphone app. Using advanced machine learning statistical techniques, this will not only provide valuable insight into the experiences of many migraine suffers as a group, it will also be able to provide you with insight into which of your triggers is really strongly associated with your migraine and which are not.
[i] This ‘textbook’ case is based on collective clinical experience, and is not based on a specific patient.
[ii] Pavlovic, J. M., Buse, D. C., Sollars, C. M., Haut, S. and Lipton, R. B. (2014), Trigger Factors and Premonitory Features of Migraine Attacks: Summary of Studies. Headache: The Journal of Head and Face Pain, 54: 1670–1679.
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