Worldwide data are extensively lacking in regard to patients with depressive symptoms under therapy with antidepressants in the primary care setting. We hypothesized that the magnitude of pain reduction under treatment with venlafaxine differently relates to regional origin of patients.

We conducted a prospective naturalistic observational trial on 420 pain sufferers with depressive symptoms from all over Switzerland who were treated with venlafaxine by 122 physicians in primary care. Previous and additional antidepressant medication was not taken into account. Physicians rated illness severity using the Clinical Global Impression severity scale and pain intensity by means of visual analogue scales.

Compared with Middle European patients (ME), those from Eastern Europe (EE), and Southern Europe (SE) were younger and presented more intense overall pain mainly affecting the head, extremities and back. In addition, SE patients suffered more intense thoracic pain than ME patients, and EE patients suffered less frequently from abdominal pain compared to their ME and SE counterparts. Furthermore, 3 months after study entry, ME patients were found to profit more from treatment with venlafaxine in terms of overall illness severity and pain intensity than patients from EE and SE.