Abstract

Objective: This study investigates the cognitive functions of cases suffering from a major depressive disorder using the auditory event related potential (AERPs) values. Method: 25 healthy controls and 25 patients with a diagnosis of Major Depressive Disorder according to DSM-IV criteria are included in the study. Latency and amplitude values of the event related potentials of all cases are recorded using the oddball paradigm. Patients having an Hamilton Depression Rating Scale score above 16 are accepted for the study. The anxiety level of the cases are evaluated using The Hamilton Anxiety Rating Scale. Results: The depressive group showed a significantly higher latency in N100, N200 and P300 and a significantly lower P300 amplitude than healthy controls. Conclusion: The increase of N200 and P300 latency and the decrease of the P300 amplitude indicated the impairment of the cognitive functions among depressive patients. The impairment of the cognitive functions in depressive patients can be represented as a dysfunction including a slowdown in mental processes and difficulties in decision making. Future studies combining the methods of neuroradiology and neurophysiology may contribute more to enlighten the etiologic factors related to the development of major depressive disorder.

Key words: Event-related potentials, P300 component, cognition