Memory scanning and retrieval in affective disorders

Previous studies have consistently demonstrated unimpaired memory scanning and retrieval in schizophrenic patients. Using the choice-reaction time paradigm, this study assessed the speed of short-term memory processing for pictorial information in both unipolar and bipolar depressives by comparing it with that of schizophrenics. It was found that the processing rate is comparable between depressives and schizophrenics, between unipolar and bipolar depressives, and between depressives on medication and those not on medication. It was concluded, therefore, that the short-term memory scanning and retrieval processes are not impaired in depressive patients. The results further suggested that the depressives' slowness often found in simple reaction time tasks may result from a dysfunction in their stimulus encoding and/or response execution rather than in the central information-identification process.