New research shows that migraine and depression may share a strong genetic component.

"Understanding the genetic factors that contribute to these disabling disorders could one day lead to better strategies to manage the course of these diseases when they occur together ," said Dr. Andrew Ahn, who wrote an editorial accompanying the study and is a member of the American Academy of Neurology. "In the meantime, people with migraine or depression should tell their doctors about any family history of either disease to help us better understand the link between the two."

The study involved 2,652 people who took part in the larger Erasmus Rucphen Family study. All of the participants are descendants of 22 couples who lived in Rucphen in the 1850s to 1900s.

"Genealogical information has shown them all to be part of a large extended family, which makes this type of genetic study possible," said study author Gisela M. Terwindt.

Of the participants, 360 had migraine. Of those, 151 had migraine with aura, which is when headaches are preceded by sensations that affect vision, such as seeing flashing lights, and 209 had migraine with no aura. A total of 977 people had depression, with 25 percent of those with migraine also having depression, compared to 13 percent of those without migraine.

The researchers then estimated the relative contribution of genetic factors for both of the disorders. They found that for both types of migraine, the heritability was estimated at 56 percent, i.e., 56 percent of the trait is explained by genetic effects. For migraine with aura, the estimate was 96 percent. "This finding shows that migraine with aura may be a promising avenue to search for migraine genes," Terwindt said.

Comparing the heritability scores for depression between those with migraine and those without showed a shared genetic component in the two disorders, particularly with migraine with aura. "This suggests that common genetic pathways may, at least partly, underlie both of these disorders, rather than that one is the consequence of the other," Terwindt said.
References:
1. Gisela M. Terwindt, et al. Shared genetic factors in migraine and depression. Evidence from a genetic isolate. Neurology, Dec 2007; 69: 2170 - 2176. doi:10.1212/WNL.0b013e3181cbcd19