P300 evidence of cognitive inflexibility in female adolescents at risk for recurrent depression

Studies utilizing the P300 event-related potential (ERP) to document potential neurophysiological deficits related to depression have produced variable findings. The present investigation examined the effects of two tasks to determine whether one task would be more sensitive to a history of depression. We examined 124 female subjects, aged 14-20 years. Each subject was assigned to either a history of depression (DEP-Hx) or control group based on the presence versus absence of a DSM-III-R Major Depressive Episode. ERPs were recorded during two auditory oddball tasks. The first task was a simple two-pitch auditory discrimination and the second task was a three-stimulus auditory discrimination. In both tasks, subjects responded to the same rare target tone. Analysis of P300 amplitudes indicated a significant group by task interaction. Simple effects indicated that control subjects exhibited smaller target P300 amplitudes during the three-stimulus task as compared to the two-stimulus task. In contrast, subjects with a history of depression did not show a significant difference in P300 target amplitude between the two tasks. These results suggest that depression history as well as task difficulty/modality may influence the utility of the P300 in documenting the neurophysiological aspects of depression. (C) 2004 Elsevier Inc. All rights reserved.