Prevalence and diagnostic distribution of medically unexplained painful somatic symptoms across 571 major depressed outpatients

Objective: To assess the prevalence and distribution of medically unexplained painful somatic symptoms (PSSs) versus nonpainful somatic symptoms (NPSSs) in patients diagnosed with major depressive episode (MDE). Method: A total of 571 outpatients diagnosed with MDE according to DSM-IV-TR criteria were consecutively enrolled into a cross-sectional, multicentric, observational study over a period of 7 months. Subjects were evaluated by means of the ad hoc validated 30-item Somatic Symptoms Checklist (SSCL-30) and Zung's questionnaires for depression and anxiety. The 32-item Hypomania Checklist (HCL-32) was also administered in order to explore any eventual association of PSSs or NPSSs with sub-threshold (DSM-IV-TR [Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision] not recognized) bipolar disorder (BD). Results: In our sample, just 183 patients (32%) did not report painful somatic symptoms (NPSSs). Of these, 90 patients (15.76%) had no somatic symptoms at all. The remaining 388 (68%) had at least one PSS being subdivided as follows: 248 (43%) had one or two PSSs, while 140 (25%) experienced two or more. Patients with at least one PSS also reported a greater number of nonpainful somatic symptoms than NPSS. Bipolar patients (associated with higher HCL-32 scores) were less represented across PSS cases than NPSS subjects. Conversely, females were more prone to having a higher number of total somatic symptoms (and bipolar features). Conclusion: PSSs are common in patients with MDE, especially among those patients reporting fewer somatic symptoms in general as opposed to those patients who exhibit more somatic symptoms (both PSSs and NPSSs) with lower relative number of PSSs. A major therapeutic implication is that antidepressant monotherapy could be used with more confidence in unexplained PSS patients than in NPSS patients because of the latter group's lower frequency of (sub)-threshold bipolar features.