Introduction

Depressive symptoms are frequently observed in schizophrenia. On average, a depression-like syndrome is occurring during the longitudinal course of schizophrenia in about 25% of the patients (Addington et al., 2002). Nevertheless, depressive symptoms do not belong to the diagnostic criteria for schizophrenia (ICD-10, DSM-IV), and it is relatively recently that stronger attempts have been made towards cross-sectional and longitudinal assessment with the new technologies to better understand the course and nature of this syndrome. The question still remains, however, whether depressive symptomatology in schizophrenia is the same as in depression. This question is at the core of this chapter which aims at analyzing similarities and differences in affective-emotional dysfunction in depressive syndromes. The chapter reviews findings from different empirical perspectives and thereby contributes to the ongoing discussion on the nosological specificity of depression in schizophrenia.

Differential diagnosis

According to Siris et al. (2001), differential diagnosis is hampered by difficulties associated with distinguishing between depressive symptomatology and certain features of schizophrenia (particularly negative symptoms), side-effects of treatment (e.g., akinesia), and difficulty of recognizing depression in the presence of florid psychosis. The following chapter gives a short overview on those factors to be considered in the differential diagnosis of depressive symptoms in schizophrenia.