Migraine and depression: do they have common causes?

Unfortunately, migraine and depression quite often occur together. Many people with migraine also experience depression, and the reverse is true too.

Researchers have been looking into why these two conditions so often occur in the same people and seem to run in families, and have come up with some ideas about what might be behind the connection. One area of research is whether migraine and depression might share underlying causes or mechanisms. In this article, we’ll explore these possibilities and what they could mean for preventing headaches.

Migraine: common and rarely comes alone

How many people have migraine? It’s hard to pinpoint, as estimates vary between studies. The figures suggest that migraine affects between 14% and 20% of the population. More recent statistics from the German Neurological Society (DGN) put the one-year prevalence (the percentage of the population that experiences migraine at least once in a given year) at between 10% and 15%. Genetic factors have long been known to play a role in migraine. We now know of more than 100 genes – sections of our genetic material – in which small changes may contribute to the development of migraine.

We’ve already looked at some of the conditions that occur alongside migraine, known as “comorbidities”, including high blood pressure, epilepsy, and stroke. Research has also pointed to a link between migraine and mental health conditions. These include depression and anxiety disorders, both of which are common, affecting approximately 8% (anxiety) and 12% (depression) of the population, respectively. Research has also demonstrated that the relationship between migraine and depression works both ways: having migraine increases the risk of developing depression, while depression increases the risk of developing migraine. This is known as a “bidirectional” relationship, meaning it works both ways. Links like these are particularly common when two conditions share biological causes.

Genetic changes in the spotlight

Researchers have already found quite a few clues pointing to possible common causes. The study of heredity, or genetics, provides important insights in research in this area. Studies have identified a wide range of changes in human genetic material, each with different effects. Some changes affect the central processes involved in how pain signals are transmitted and perceived. Others are involved in regulating blood circulation and inflammatory processes in the nervous system, or influence the production and distribution of chemical messengers that help regulate these processes.

The sheer volume of research published on this subject in recent years has helped to shed light on some of these connections. It seems that a variety of genetic changes plays an important role in both migraine and depression. However, researchers have not been able to identify a single cause that would explain why these two conditions occur together. Rather, a whole range of genes – that is, sections of our genetic material – appear to be involved.

Shared pathways in the development of migraine and depression

A review by a group of researchers from Poland provides a detailed look at the chemical messengers and other substances that could play a role in both conditions. Let’s take a look at some examples.

1. Signals in the nervous system:

The brain contains a number of chemical messengers that transmit signals through the central nervous system. These are known as neurotransmitters. One of these messengers, serotonin, is less readily available in people with depression than in people without the condition. Interestingly, low levels of serotonin can also affect the transmission of pain signals. In turn, this can affect people with migraine by making them more sensitive to pain. This common feature can be explained by changes in genetic material (mutations). In both conditions, researchers have found mutations in a gene responsible for producing a protein that transports serotonin into cells. A malfunction at this point could therefore affect both conditions.

2. Inflammatory messengers:

Research suggests that the molecule CGRP (calcitonin gene-related peptide) plays a major role in the development of migraine attacks. We looked at this in more detail in an earlier post. CGRP can widen our blood vessels. This helps maintain adequate blood flow, ensuring that the brain is well supplied with oxygen and nutrients. However, CGRP is also involved in the development and regulation of inflammatory processes – two factors that have been repeatedly implicated in triggering migraine attacks. Elevated levels of CGRP have also been detected in animal models of depression, pointing to a possible causal relationship.

3. Hormones:

The female sex hormone oestrogen could also be involved in both conditions. It has a range of effects on how signals and information are transmitted through the nervous system. This is particularly interesting when it comes to serotonin and noradrenaline. Both of these chemical messengers have been shown to play a role in depression and in the transmission of pain. Pain transmission, in turn, is central to migraine. So here, too, the two conditions may have some triggers in common.

4. Environmental factors such as stress:

Stress, and especially prolonged stress, can play a major role in triggering migraine. We’ve already explored the link between these factors in a previous article. Stress is one of the most powerful triggers of migraine attacks and needs close attention in any prevention strategy. If stress keeps building and eventually becomes a permanent part of life, migraine can also become a chronic condition. There also seems to be a link with depression: Stress can affect both the body and the mind, and these effects can in turn make depression worse or even cause it to become chronic.

5. Heredity:

Genes also influence our susceptibility to both conditions. Studies in twins and other close relatives have found that family members of people with migraine had an increased risk of developing depression. The reverse was also true: relatives of people with depression were more likely to develop migraine. Interestingly, these links were stronger in identical twins than in fraternal twins. Taken together, these findings suggest that there are shared genetic factors that could help explain the link between migraine and depression.

Nothing is inevitable

Although migraine and depression are linked, this is not to say that everyone with migraine will necessarily develop depression. The more you understand your own migraine, the more opportunities you will discover to prevent attacks or at least make them less severe. One particularly effective approach is to identify your personal migraine triggers and learn how to manage them, and ultimately reduce the impact of migraine on your life. It’s also important to get proper medical care. For most people with migraine, simply knowing that you’re not alone in dealing with it can be a huge step forward. Our resources are designed to help people build expertise and take an active, informed role in managing their headaches. Our website “Prevent Headache“ gives you all the key information you need, while the app provides extra support for living with migraine day to day. The better you understand and manage your migraine, the more in control you can feel. And that could also help you cope better with depressive moments.