Clinical symptoms of major depression are associated with the intensity dependence of auditory event-related potential components

The intensity (loudness) dependent amplitude change (IDAP) of the auditory event-related potential (ERP) has been shown to be associated with the outcome of treatment with selective serotonin reuptake inhibitors in major depression. The purpose of the present study is to evaluate associations between clinical symptoms of major depression and the IDAP as an indirect indicator of cortical serotonergic function. We assessed 40 in-patients suffering from a major depressive episode (DSM-IV) prior to antidepressant treatment. Psychometric characteristics of depression were assessed by means of psychiatric rating scales (CGI, HDRS, HAMA, STAI and BDI) and evaluated for associations with auditory evoked P1, NI, P2 as well as P1/N1 and N1/P2 peak to peak amplitude slopes. Our data revealed a positive correlation of the intensity dependent N1 amplitude slope with the degree of certain somatic symptoms of depression: loss of appetite and weight, insomnia, and sexual dysfunction. The results of our study might contribute to a more specific clinical basis in the differential indication of serotonergic versus noradrenergic antidepressants. (C) 2008 Elsevier Ireland Ltd. All rights reserved.