[Distinguishing depressive from nondepressive patients in schizophrenia in terms of symptomatology]

Schizophrenia is a syndrome with five dimensions and it contains positive symptoms, negative symptoms, disorganization, depression, and cognitive symptoms. Depression which is one of these dimensions can be seen with every dimension and in every phase of schizophrenia. In this study our aim was to examine the overlapping features and the discriminating symptoms of depression comorbid with schizophrenia.

The subjects consisted of 30 patients diagnosed as schizophrenic with a concurrent depression, disorder, and 30 patients diagnosed as schizophrenic without a concurrent depression, admitted to the outpatient department of two university hospitals. Patients were assessed using the following measures: Calgary Depression Scale for Schizophrenia (CDSS), Scales for Assessment of Positive and Negative Symptoms (SAPS and SANS respectively), and Extrapyramidal Symptom Rating Scale (ESRS).

For determining the overlapping features of schizophrenia with depression, symptoms drawn from SAPS, SANS and ESRS were correlated with CDSS score, and affective flattening, apathy, attention, and delusions were significantly correlated with total score of CDSS. By Wilks' Lambda method, the discriminating symptoms of the depressive and schizophrenic patients from the only schizophrenic patients were found to be depressive mood and feelings of worthlessness.

The shared nature of the overlapping features and discriminating symptoms is the emotional component affecting the presence of depression comorbid with schizophrenia. Negative affectivity is the dominance of negative-loaded feelings in the emotional component. In symptomatology, the presence of negative affectivity in the emotional component is suggested to be a specifier for depression in schizophrenia.