Chronic headaches, particularly migraines and those that are disabling, in conjunction with severe somatic symptoms --physical symptoms of a psychological origin rather than a physical source -- greatly increase the risk of major depressive disorder in women, according to a report in the medical journal Neurology.

"The literature on chronic headaches and depression is fairly robust. A number of studies have shown that headache patients are predisposed to depression," lead author Dr. Gretchen E. Tietjen, from the University of Toledo-Health Science Campus in Ohio, told Reuters Health. "The novelty of our study was the inclusion of somatic symptoms, which was only previously investigated in one small study."

The results suggest that "chronic headache, disabling headache, and severe somatic symptoms work synergistically to increase the risk of depression," Tietjen said.

Alone, the presence of chronic headache had little effect on the risk of depression compared with the effect of the combination of mild episodic headaches and minimal somatic symptoms. When the headaches become more disabling and the somatic symptoms more severe, however, the risk of depression increased markedly.

Very disabling, chronic headaches increase the odds of depression by 3.6-fold, and by 4.1-fold if the headaches are migraines, the report indicates. If severe somatic symptoms are also present, then the odds ratios climb to 25.1 and 31.8 for all headaches and for migraines, respectively.

These findings are from a study of more than 1,000 women who were seen at outpatient headache centers between June 2003 and December 2004. The subjects included 593 with episodic headaches and 439 with chronic headaches. Ninety-six percent of patients with episodic headaches and 87% with chronic headaches had migraines.

Somatic symptoms were assessed using a questionnaire on 15 symptoms, such as stomach pain, limb pain, sleeping problems, nausea and palpitations.

Low levels of education and income were associated with both chronic headache and severe disabling headache, the report indicates.

"People with chronic headaches tend to have a lot of...somatic complaints," such as irritable bowel, pelvic pain and fibromyalgia, Tietjen noted. The study results indicate that the coexistence of these conditions dramatically increases the risk of depression, she added.

Tietjen said that her team has a study that is now being reviewed for publication, which evaluated the impact of abuse in women with chronic headaches. "What we found is that childhood abuse and sexual abuse is much more common in women with headaches and depression" than in those with headache alone.