Abstract

Objective: Patients with major depression often have psychomotor retardation, reduced mental processing speed, inability to make decision. These symptoms may be mediated in prefrontal abnormalities (cortico-striato-pallido-thalamo-cortical pathway). This study investigated the prefrontal abnormalities in cases suffering from a major depressive disorder using the event related potentials (AERPs). Method: 25 healthy persons and 25 patients with a diagnosis of Major Depressive Disorder acoording to DSM-LV 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 a Hamilton Depression Rating Scale score over 16 are included in the study. The anxiety level of the cases are evaluated using The Hamilton Anxiety Rating Scale. Results: The comparison of the AERP findings showed an increase of the latency and a reduction of the amplitude of P300. Significant event related potential differences were more prominent at frontal regions. Conclusions: Dysfunctions of the frontostriatal pathways are thought to play an important role in the aetiology of major depression. The results of this study confirmed the role of frontal lohe dysfunctions in major depressive disorder. Future studies combining the methods of neuroradiology and neurophysiology may contribute more to enlighten the aetiological factors related to the development of major depressive disorder.

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