Somatic Symptoms in Headache Patients: the Influence of Headache Diagnosis, Frequency, and Comorbidity

Background: Mood disorders of anxiety and depression are well known to be comorbid with primary headache disorders. Less is known of the comorbidity of other somatic symptoms with headache.

Methods: Headache Clinic patients were screened with the Primary Care Evaluation of Mental Disorders (PRIME-MD), a multidimensional psychiatric screening tool. The prevalence of somatic symptoms was compared by headache diagnosis, frequency of severe headache, and psychiatric diagnosis. Follow-up data were obtained 6 months after consultation.

Results: Clinical diagnoses and PRIME-MD data were available for 289 patients. Associated somatic symptoms were more frequent in patients with chronic migraine (mean 5.5, P<.001) and chronic daily headache (CDH) (6.3, P=.008) compared to episodic migraine (4.0); in patients with severe headache >2 days per week compared to <or=2 days per week (6.15 vs. 4.15, P<.001); and in patients with a clinical diagnosis of anxiety or depression, or both, compared to no anxiety or depression, (5.7, P=.05, 5.2, P<.05, and 6.8, P<.001, respectively, vs. 4.5). The most common specific symptoms were fatigue (73%), sleep difficulty (60%), and nausea/indigestion (55%). Compared to a primary care sample, patients with severe headache >2 days per week had significantly higher somatic counts (P=.01). Six-month follow-up data were available for 140 patients. Associated symptoms decreased both for patients with and without decrease in severe headache frequency (mean reduction of 1.0, P=.01 and 0.8, P=.003, respectively).

Conclusion: Associated somatic symptoms are more common in patients with chronic migraine and CDH, with more frequent severe headaches, and with associated anxiety or depression. Patients with episodic migraine have similar somatic prevalence as a previously studied primary care population. The spectrum of headache disorders may be characterized as showing increasing somatic prevalence as headaches, particularly severe headaches, become more frequent.