Migraine and Depression: Common Genetics

There have been several studies showing the increased rates of depression in those with migraine and increased rates of migraine in those with depression.  Drugs that target the neurotransmitter serotonin form the key strategy for the treatment of both disorders.

Now a twin study using the University of Washington Twin Registry supports the roll of common genetic factors in these two disorders.

Twin studies form a key method to examine both the genetic and environmental contributions to risks for a variety of conditions.  Monozygotic twin (identical twin) concordance rates (or rates of sharing of a disorder) are compared to dizygotic twin (fraternal twin) concordance.  Monozygotic twins share more genes than dizygotic twins allowing for an estimate of the genetic contribution to disorders.

Schur and colleagues applied the twin method to a group of over 1000 female twin pairs.  They focused on twins with both migraine and depression examining the genetic and environment contributions to the co-occurrence of these conditions.

Using a self-report of physician diagnosis of migraine and depression the study found a rate of depression of 23% and a rate of 20% for migraine headache in the study sample.  Eight percent of the sample reported both depression and migraine.  These rates are consistent with other studies of the community prevalence of the two conditions.

Using standard twin study statistical techniques the authors estimated:

• Heritability for depression was estimated at 58%
• Heritability for migraine was estimated at 44%
• Twenty per cent of the variability of depression and migraine was due to shared gene effects
• Four per cent of the variability of depression and migraine was due to shared unique environmental factors

The authors note that to date, no specific chromosomal locations have been identified to overlap between migraine and depression.  Nevertheless they note in future studies "investigators could conduct association studies that use candidate gene or whole-genome approaches in samples selected for the presence of both depression and migraine".  They hope such strategies might provide insight into the pathophysiology and treatment of the two conditions.

Photo of Juno Beach, Florida sunrise using filter effect from the author's collection.

Schur EA, Noonan C, Buchwald D, Goldberg J, & Afari N (2009). A twin study of depression and migraine: evidence for a shared genetic vulnerability. Headache, 49 (10), 1493-502 PMID: 19438739