If findings of the study are anything to go by, the two apparently isolated problems may have the same genetic connection.

"Migraine and depression co-occur far more frequently within subjects than to be expected by chance," said lead researcher Dr. Gisela M. Terwindt, an assistant professor of neurology at Leiden University Medical Center.

"This relationship is bidirectional; migraine patients have an increased risk to develop depression and, vice versa, depressed subjects have an increased risk of getting migraine attacks," she said.

Migraine is a common type of headache accompanied with agonizing pain in one side of the head. The symptoms include nausea, vomiting, or sensitivity to light.  Some people may have a symptom called an aura before the actual headache begins. An aura usually includes odd sensations, mainly vision disturbances.

Migraine sufferers studied
Dutch scientists looked at 2652 people who participated in a research program called the Erasmus Rucphen Family study to come with these findings.

Of these, 361 participants had migraine including 151 subjects who suffered from migraine with aura--when headaches are preceded by sensations such as flashing lights. Also, overall 977 participants had depression.

The migraine sufferers were compared with 617 participants who did not suffer from the incapacitating condition.

Based on the medical records, the scientists found that 25 percent of those who had migraine also suffered from depression compared to 13 percent of those who did not suffer from the unbearable condition.

Shared genetic factor found
Using the same data, the researchers then analyzed whether these disorders had a common genetic link.

The heritability (the percentage explained by genetic factors) in both types of migraine was estimated at 56 percent. And specifically for people with migraine with aura, the heritability accounted for was 96 percent.

On comparing the heritability scores for depression with those who had migraine and those without the condition, the researchers found a shared genetic component in both the disorders, particularly in migraine with aura. “We found an increased risk of depression and depressive symptoms in migraine patients, in particular those with aura,” Terwindt said.

Findings useful The researchers are hopeful that findings of the study are likely to have important implications for better treatment and potential prevention of both the conditions. "Identification of common genetic factors may significantly improve the insight into the molecular basis of both migraine and depression," Terwindt said.

"This may help in the future to get more insight in the common pathophysiological process underlying both of these disabling disorders. This will, hopefully, lead to prevention of chronic migraine and development of tailored prophylactic treatments." The study appears in the online edition of Neurology, the medical journal of the American Academy of Neurology.