Research presented at the recent Canadian Psychiatric Association annual conference suggests strong links between migraine headaches and bipolar I disorder (40% higher than healthy subjects), based on a community survey of 37,000 people. It proposes a subtype of bipolar disorder with migraine, and recommends screening.
Amongst males, 14.9% of those with manic episodes were also diagnosed with migraines compared with 5.8% of the general population (P < .05). Amongst females, 34.7% had both migraines and bipolar disorder compared with 14.7% who only had migraines (P < .05). Dr. McIntyre concluded that not only do migraines differentially affect those with bipolar disorder and is more prevalent than in the general population it results in a more severe illness for men. Males with BDM [bipolar disorder with migraine] have a more harmful dysfunction as evidenced by an earlier age of onset, more anxiety co-morbidity, greater use of multiple medications, disability and welfare payments, subjective ratings of health and utilization of medical services.
Women tended to have more comorbid medical conditions (such as asthma) and required more help with daily living activities.
Migraine has also been associated with bipolar, depression, and anxiety disorders (especially panic disorder) in other studies. A French analysis provides another set of more conservative statistics; incidence of disorders in with migraine compared to without:
Depression – 34.4% vs. 10.4%
Bipolar I – 6.8% vs. 0.9%
Panic disorder – 10.9% vs. 1.8%
Generalized anxiety disorder – 10.2% vs. 1.9%
Obsessive-compulsive disorder (OCD) – 8.6% vs. 1.8%
These were both community-wide studies, while a Norwegian article examining a sample of psychiatric inpatients concludes:
Symptoms of migraine were found to be common in these patients, both in those with unipolar depression (46% prevalence of migraine) and in those with bipolar disorders (44% prevalence). Among the bipolar patients there was, however, a striking difference between the two diagnostic subgroups, with a prevalence of 77% in the bipolar II group compared with 14% in the bipolar I group (P = 0.001). These results support the contention that bipolar I and II are biologically separate disorders.
It’s been suggested that patients with unipolar depression and migraine should be screened for bipolar, as it may be an indicator of this separate phenotype.
I couldn’t find much research, at this time, suggesting reasons for the correlations (beyond noting that migraine and bipolar disorders both involve the serotonergic system, and valproate can be effective). As the French study notes, “…no psychopathological, biological or genetic explanation seems to be meaningful.” Epidemiological surveys are a start; hopefully specific neuropsychiatric studies of the causes will also emerge.
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Read more (subscription required) details from The Prevalence and Impact of Migraine Headache in Bipolar Disorder: Results From the Canadian Community Health Survey, McIntyre et al., 2006, Headache: The Journal of Head and Face Pain; as well as the free abstract (article not online) of Mental disorders and migraine: epidemiologic studies, Guillem et al., 1999, L’Encéphale. Also see (subscription required) The prevalence of migraine in patients with bipolar and unipolar affective disorders, Fasmer OB, 2001, Cephalalgia.
Read more about migraine physiology in New Models of Migraine, a consumer publication from the Society for Neuroscience.