What are comorbid conditions?

With any disease or disorder, it's not uncommon for them to be associated with other comorbid conditions. Comorbid conditions are conditions that occur together, but neither causes the other. There may or may not be an understood physiological link between the conditions, but that's not the same as one causing the other.
 

Migraine disease and depression

It has been established that Migraine disease and major depressive disorder (clinical depression) are frequently comorbid. A study published in 2000 demonstrated that while depression affects 17% of the general population, it affects 47% of Migraineurs.¹ Dr. Richard Lipton stated,

"It seems logical Migraine patients would be depressed because of their pain, but it goes the other way too -- depressed patients are more likely to have Migraine. We think the two disorders must have a common neurobiology."

On studies linking Migraine and Depression, Dr. Stephen Silberstein commented,

". . . really tell us that Migraine is a double whammy. They tell us that Migraine is really devastating, and that the conditions associated with Migraine are devastating."
 

Migraine disease and bipolar disorder

a 2003 study

More recent studies have now shown Migraine disease seems to be comorbid to bipolar disorder. A 2003 study showed that the prevalence of Migraine disease among patients with bipolar disorder was high enough for the researchers to conclude,

"Bipolar disorder with migraine is associated with differences in the clinical course of bipolar disorder, and may represent a subtype of bipolar disorder."²

In that study,

• 108 patients were enrolled and evaluated.
• Prevalence of Migraine in patients with bipolar disorder was 39.8% - 43.8% among women, 31.4% among men. The prevalence in the general population is 12% - 18% of women, 6-8% of men.
• Prevalence of Migraine in patients with bipolar II disorder, was 64.7% - 75% of women, 40% of men. (see graph below)

a 2006 study

A 2006 study based on the Canadian Community Health Survey (CCHS), provided somewhat different prevalence statistics, but still showed a clear comorbidity and elicited this conclusion from the authors,

"Bipolar disorder with comorbid migraine is prevalent and associated with greater dysfunction and medical service utilization..."³

In that study,

• 938 patients were identified and evaluated out of the 36,984 who completed the CCHS.
• Prevalence of Migraine was 24.8% - 34.7% for women, 14.9% for men. The prevalence of Migraine in respondents without bipolar disorder was 14.7% for women, 5.8% for men.
• The odds of Migraine in people with bipolar I disorder were 40% higher than people without bipolar disorder. (see graph below)

The authors commented,

"Both bipolar males and females had a significantly higher prevalence of migraine when compared to the general population. Males with BDM (screened positive for a manic episode and migraine) have a more severe illness course and more harmful dysfunction as evinced by earlier age of onset, more anxiety comorbidity, greater use of multiple medications, disability and welfare payments, subjective ratings of health, and utilization of medical services."

They also echoed a conclusion from the 2003 study,

"The BDM phenotype may comprise a subphenotype of bipolar disorder, which is salient to pathophysiological models of these syndromes."
 

Summary

These studies evaluated patients with bipolar disorder for Migraine disease and established a clear comorbidity. It would be interesting and potentially beneficial to see similar studies conducted in patients with Migraine disease to investigate whether there's a correspondingly increased incidence of bipolar disorder among Migraineurs.

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Resources:

¹ R. B. Lipton, MD, S. W. Hamelsky, MPH, K. B. Kolodner, ScD, T. J. Steiner, MB, PhD and W. F. Stewart, PhD, MPH. "Migraine, quality of life, and depression." Neurology 2000;55:629-635.

² Low, Nancy C. P., du Fort, Guillaume Galbaud & Cervantes, Pablo (2003) Prevalence, Clinical Correlates, and Treatment of Migraine in Bipolar Disorder. Headache: The Journal of Head and Face Pain 43 (9), 940-949. doi: 10.1046/j.1526-4610.2003.03184.x

³ McIntyre, Roger S., Konarski, Jakub Z., Wilkins, Kathryn, Bouffard, Beverley, Soczynska, Joanna K. & Kennedy, Sidney H. (2006) The Prevalence and Impact of Migraine Headache in Bipolar Disorder: Results From the Canadian Community Health Survey. Headache: The Journal of Head and Face Pain 46 (6), 973-982. doi: 10.1111/j.1526-4610.2006.00469.x

Published July 14, 2006
© Teri Robert