Pre-treatment EEG and it's relationship to depression severity and paroxetine treatment outcome.

An array of variables have been assessed as potential early predictors of antidepressant response in depressed patients. This exploratory study examined the relationship of clinical outcome, following pharmacotherapeutic treatment, with quantitative electroencephalographic (EEG) features assessed prior to treatment onset. In 70 major affective disorder patients, pre-treatment spectrum-analysed topographic EEG indices (absolute power, relative power, mean frequency, inter-hemispheric power asymmetry and coherence for 4 frequency bands) were assessed in relation to baseline HAM-D ratings and HAM-D rating changes following 6 weeks of open-label paroxetine treatment. EEG slow wave (theta) activities were positively correlated with depression ratings prior to treatment. Of the patients (n = 51) completing treatment, 80% evidenced a >50% reduction in HAM-D ratings. Improved rating changes in general were found to be negatively related to slow (delta and theta) wave activity and positively related to fast (beta) activity at frontal recording sites. Findings are discussed in relation to the neurochemistry and neurobiology of depressive disorders.