[Depression in schizophrenia: Relationship with other symptoms, differential diagnosis, prognosis,treatment]

The relationship between depressive symptoms and other symptom categories in schizophrenia have been studied by many authors. According to the existing studies depression in schizophrenic patients is related to the presense of positive symptoms, especifically delusions and hallucinations.As far as negative symptoms concerns it seems that there coexist with the depressive symptoms in any phase of the disease at least in a subgroup of schizophrenic patients. In addition, according to the pyramidal model of Kay, when positive and depressive symptoms coexist, they create theclinical picture of the paranoid subtype of schizophrenia. The same holds for the combination of negative and depressive symptoms, which most frequently describe the residual subtype of the disease. Extrapyramidal symptoms are side effects of antipsychotic drugs (especially the classicalones). According to the existing literature it seems that antipyramidal side effects appear more often in schizophrenic patients with depressive symptoms. The differential diagnosis of depressive symptoms in schizophrenic patients should start with the evaluation of possible presence of organiccauses like somatic disease, medication induced extrapyramidal symptoms, substance abuse. Yet, symptoms of depression need to be differentiated from the negative symptoms of schizophrenia. Psychiatric syndromes like schizoaffective disorder, bipolar disorder and depression with psychotic features need to be also considered. In this case is very important to identify accurately the duration of depressive symptoms as well as the succession of appearance of the depressive vs. psychotic symptoms. Depressive symptoms appear to be bad prognostic sign for the long-term outcome of schizophrenia, because of the increased risk for suicide but also because of the worsening of the quality of life and the general wellbeing of the schizophrenic patient. Depressive symptoms during the acute phase of the disease usually respond to antipsychotic therapy, but in some cases the treating physician may consider the use of atypical antipsychotics. In the case of post psychotic depression the concurrent administration of antidepressants is indicated.