Characterisation of depression in patients with schizophrenia.

Background & objectives: Though number of studies have examined the prevalence of depression at different phases of the schizophrenic illness, the precise nature of depressive symptoms present in different phases of the schizophrenic illness remains unclear. We therefore undertook this study to characterize and compare the profile of depressive symptoms in acute and chronic schizophrenia with those in major depression. Methods: Three groups of patients with (i) an acute schizophrenic episode, (ii) stable schizophrenia and (iii) primary major depression, were compared on demographic variables and on clinical rating scales for depression and the positive and negative syndrome scale (PANSS). Results: The clinical depression seen in acute schizophrenia and primary depression differed significantly from that seen in chronic schizophrenia. This was confirmed by factor analysis which showed that selective subsets of symptoms were more likely to differentiate the three groups clinically. Further, the depression in chronic schizophrenia was less likely to be associated with life events and was best detected by using the Beck depression inventory (BDI). Interpretation & conclusions: Careful analysis of depressive symptoms can differentiate between the three groups - this would also imply that the underlying pathogenetic mechanism for depression in the groups may be different. Our findings support the use of the BDI to identify depressive symptoms in chronic schizophrenia so that appropriate early intervention can be targeted.