Psychiatric comorbidities of chronic migraine in community and tertiary care clinic samples

Although the association between episodic migraine and psychiatric comorbidities is well documented, few studies have focused on the comorbidity with chronic migraine (CM) and discrepancies exist between population-based and clinic-based data. The objective of this study is to compare demographic and psychiatric comorbidity correlates between CM samples drawn from the community and tertiary care. All inhabitants from a city borough were interviewed for the presence of headaches occurring 15 or more days per month. CM was diagnosed after subjects had been interviewed and examined by a headache doctor. Participants were also assessed with a structured interview by a psychiatrist, who assigned diagnoses based on the DSM-IV. The same investigators assessed all patients consecutively seen in a university-based outpatient headache center over a 4-month period. The samples consist of 41 individuals from the community and 43 from the headache center. Sociodemographic profiles were similar between groups with the exception of the mean number of years of formal education. Among individuals from the community, psychiatric diagnoses were present in 65.9 % of cases, relative to 83.7 % in those from the headache center (p = 0.06). Phobias (41.9 vs. 29.3 %) and depression (32.6 vs. 29.3 %) were more frequent in patients from the headache center, but this difference did not reach statistical significance. Thus the frequency of psychiatric disorders in patients with CM was elevated in both settings, being higher in the specialty care clinic.