A. Oguz

P300 changes in major depressive disorders with and without psychotic features

BACKGROUND Although there are many P300 studies in depressive patients, only a few studies have focused on the effects of psychotic features in depression and of response to antidepressant treatment on P300. This study was designed to investigate possible differences in the P300 component of event-related potentials in depressed patients with and without psychotic features and if any, to see whether these changes altered with treatment of depression. METHODS Thirty-six patients with major depressive disorder diagnosed according to DSM-IV, and 20 healthy control subjects were involved in the study. Sixteen of the patients had psychotic features. Auditory P300 was recorded before treatment and after remission. RESULTS Pretreatment P300 latencies were significantly prolonged both in patients with and without psychotic features compared to controls. Pretreatment P300 amplitudes were significantly decreased only in the patients with psychotic features. After treatment of depression, delayed P300 latencies in both patient groups and decreased P300 amplitude in the patient group with psychotic features were normalized. LIMITATIONS The medication status of the patient was heterogeneous. CONCLUSION Since the impairment seems to be improved by drug treatment, prolonged P300 latency might be a state marker for a major depressive episode, and decreased P300 amplitude which is correlated with paranoid ideation might be more associated with psychotic subtype.

The regional cerebral blood flow changes in major depressive disorder with and without psychotic features

Depressive patients with psychotic features demonstrate distinct biological abnormalities in the hypothalamic-pituitary-adrenal axis (HPA), dopaminergic activity, electroencephalogram sleep profiles and measures of serotonergic function when compared to nonpsychotic depressive patients. However, very few functional neuroimaging studies were specifically designed for studying the effects of psychotic features on neuroimaging findings in depressed patients. The objective of the present study was to compare brain Single Photon Emission Tomography (SPECT) images in a group of unmedicated depressive patients with and without psychotic features. Twenty-eight patients who fully met DSM-IV criteria for major depressive disorder (MDD, 12 had psychotic features) were included in the study. They were compared with 16 control subjects matched for age, gender and education. Both psychotic and nonpsychotic depressed patients showed significantly lower regional cerebral blood flow (rCBF) values in the left and right superior frontal cortex, and left anterior cingulate cortex compared to those of controls. In comparison with depressive patients without psychotic features (DwoPF), depressive patients with psychotic features (DwPF) showed significantly lower rCBF perfusion ratios in left parietal cortex, left cerebellum but had higher rCBF perfusion ratio in the left inferior frontal cortex and caudate nucleus. The present study showed that DwPF have a different rCBF pattern compared to patients without psychotic features. Abnormalities involving inferior frontal cortex, striatum and cerebellum may play an important role in the generation of psychotic symptoms in depression.