Migraine: A missing link between somatic symptoms and major depressive disorder

Background: Research into the role of migraine in somatic symptoms of major depressive disorder (MDD) has long been neglected; hence, the aim of this study was to compare the impact of migraine and anxiety comorbidities on the somatic symptoms of patients with MDD. Methods: Consecutive psychiatric outpatients with MDD in a medical center were enrolled. MDD and anxiety disorders were diagnosed using the Structured Clinical Interview for DSM-IV-TR; migraine was diagnosed according to the International Classification of Headache Disorders, 2nd edition. Four scales were administered and evaluated: the Hamilton Depression Rating Scale, the Depression and Somatic Symptoms Scale, the somatization subscale of the Symptom Checklist-90-Revised, and the Hospital Anxiety and Depression Scale. Multiple linear regressions were used to find the most powerful comorbidities in predicting somatic symptoms. Results: One hundred and fifty five patients (106F, 49M) completed the study. Subjects with migraine had higher somatic, depression and anxiety severities. Panic disorder was the most important factor when predicting somatic severity among anxiety comorbidities. Migraine (R² change = 0.28 to 0.04, p < .01) was the strongest independent factor in predicting somatic severity, even after controlling for anxiety comorbidities and demographic variables. Limitations: This study used certain exclusion criteria when enrolling MDD outpatients, possibly introducing bias. Conclusions: Comorbidity with migraine was found to be associated with more somatic symptoms in patients with MDD, and migraine was a strong and independent predictor for the somatic symptoms of MDD. Future studies on the somatic symptoms of MDD should therefore take migraine into consideration.