Neurophysiological correlates of depressive symptomatology.

Some evidence has been presented in previous articles supporting the hypothesis that relevant relationships may occur between clinical symptoms of depression and complex EEG features investigated by means of a systemic structural analysis (SSA). The present paper deals with a closer analysis of the clinical-neurophysiological relationships in depressive syndromes. 22 untreated depressed patients of both sexes participated in the study. The patients were rated by means of the Cronholm and Ottosson Rating Scale for Depression (CORSD) at the time of the EEG investigation. Special computer programs were used to investigate the relationships between clinical symptoms and elementary EEG characteristics. It was found that symptoms comprised in the 'anxiety-depression' subscale of the CORSD were related to fast activity in the EEG, whereas symptoms comprised in the 'retardation' subscale showed significant relationship with slow EEG activity. The implicaions of these findings are discussed in terms of excitatory and inhibitory processes in the CNS. Both these processes exhibit a high degree of structural complexity and integration.