Unexplained somatic symptoms during major depression: prevalence and clinical impact in a national sample of Italian psychiatric outpatients

Background: The aim of this study was to explore the prevalence and impact of unexplained somatic symptoms during major depression. Sampling and Methods: A total of 560 consecutive outpatients with a major depressive episode according to the DSM-IV (text revision) were evaluated in 30 psychiatric facilities throughout Italy. 'Unexplained' somatic symptoms were evaluated using the 30-item Somatic Symptoms Checklist (SSCL-30). Somatic symptoms were considered explained if they were best accounted for as coming from a concomitant physical illness or side effects. Patients evaluated their own mood symptomatology using the Zung questionnaires for depression and anxiety and the Hypomania Checklist-32. Results: According to the SSCL-30, only 90 subjects (16.1%) had no unexplained somatic symptoms, while 231 (41.3%) had 1-5 unexplained symptoms and 239 (42.7%) had more than 5. Asthenia was the most commonly observed unexplained somatic symptom (53% of patients). Unexplained somatic symptoms were more common in females and among those suffering from major depression and depression not otherwise specified rather than in patients with recurrent major depression and bipolar disorders. No relationship between unexplained somatic symptoms and hypomanic features was observed. Conclusions: The presence of a large number of unexplained somatic symptoms is associated with more severe depression and higher rates of misdiagnosis and inappropriate treatment.