Depression, emotional blunting, and akinesia in schizophrenia. Overlap and differentiation

Depression, negative symptoms, and extrapyramidal signs (EPS) frequently occur together in schizophrenia. Their overlap is due partly to the lack of specificity of assessment instruments. However, to disentangle the three syndromes is clinically important as treatment of schizophrenia requires a differentiated approach. This study investigated the overlap between depression, emotional blunting as a core part of the negative syndrome, and akinesia as manifestation of EPS, using the Calgary Depression Rating Scale (CDSS), the Rating Scale for Emotional Blunting (SEB), and the akinesia score of the Simpson-Angus Scale (SAS) as the most specific assessment instruments presently available. We investigated 57 medicated schizophrenic patients before discharge from hospitalization. Mutual relationships were assessed with linear and partial correlations. Substantial linear associations emerged between SEB and SAS scores. The correlation between CDSS and SAS scores was significantly lower, but also different from zero. When SEB scores were statistically controlled, the association between CDSS and SAS scores dropped to nonsignificance; the correlation between SEB and SAS scores remained nearly unchanged when controlling for depression. The correlation between CDSS and SEB scores decreased to nonsignificance when controlling for SAS scores. Neither gender, age, illness duration, nor type of medication had an influence on the findings. High levels of akinesia were related to emotional blunting but not independently to depressive symptoms in medicated schizophrenic patients. Although the results cannot be assumed to be specific for schizophrenia, they corroborate the partial independence of depression and affective blunting in schizophrenia and the relationship of negative symptoms to EPS.