Individuals who have migraines have a higher chance of experiencing major depressive episodes, researchers from the University of Calgary, Canada, reported in the journal Headache. The authors added that the higher risk is there the other way round - that those with major depressive episodes are also at a higher risk of having migraines.

Lead author, Geeta Modgill MsC, says that those who suffer from either migraines or clinical depression should become knowledgeable regarding the signs and symptoms of the other, i.e. migraine sufferers should know about depressive symptoms, and those suffering from major depressive episodes should know about migraine symptoms.

A migraine is a particularly severe headache that is frequently preceded by some warning signs, such as blind spots or flashes of light, similar to the sensation one has after being photographed up close with a very powerful camera flash; other warning signs of a looming migraine attack may be tingling in the legs or arms, vomiting, nausea, and photophobia (heightened sensitivity to light).

Experts say that migraines occur when the blood vessels enlarge, combined with the release of chemicals from nerve fibers that surround these vessels. The artery that is located outside of the skull, just under the skin enlarges during the headache. A release of chemical triggers inflammation, pain and dilation of the artery.

The sympathetic nervous system responds during a migraine attack, making the patient feel nauseous; there may sometimes be vomiting, and even diarrhea. This response also slows down the speed at which food leaves the stomach and enters the small intestine - this affects food absorption, undermines blood circulation (resulting in cold feet and hands), and increases light and sound sensitivity.

Over 28 million adults in the USA suffer from migraines. It is much more common in females than males.

As background information to their article, the authors explained that previous (population-based cross-sectional) studies had indicated there probably is a link between migraine and depression. Longitudinal studies, however, have not demonstrated compellingly that the link works both ways.

Modgill and team set out to find out whether MDEs (major depressive episodes) were linked to a higher migraine risk in the general population, as well whether migraine might be associated with MDE risk.

They gathered data from the Canadian National Population Health Survey, which included 15,254 individuals. They were followed-up every two years from 1994 for 12 years.

They found that, overall, 15% of them had MDEs and 12% had bouts of migraine during the 12-year study period.

The researchers reported that, according to their findings:
  • Migraine sufferers have a 60% higher risk of suffering from MDEs compared to people who never have migraines
  • Those who experienced MDEs have a 40% higher chance of developing migraine, compared to people without MDEs.
In both cases, they had made adjustments for sex, age and other chronic conditions.

The investigators believe that some factors, such as childhood stress may impact on how the human brain subsequently responds to stress. Their study was not involved in finding out whether there may be some biological effects.

In an Abstract in the journal, the authors concluded:

"The current study provides substantial evidence that migraine is associated with the later development of MDEs, but does not provide strong causal evidence of an association in the other direction. Environmental factors such as childhood trauma and stress may shape the expression of this bidirectional relationship; however, the precise underlying mechanisms are not yet known."

Written by Christian Nordqvist