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 a ntidepressant response in depressed patients. This exploratory study examin ed the relationship of clinical outcome, following pharmacotherapeutic trea tment, with quantitative electroencephalographic (EEG) features assessed pr ior to treatment onset. In 70 major affective disorder patients, pre-treatm ent spectrum-analysed topographic EEG indices (absolute power, relative pow er, mean frequency, inter-hemispheric power asymmetry and coherence for 4 f requency 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 ra tings prior to treatment. Of the patients (n = 51) completing treatment, 80 % evidenced a > 50 % reduction in HAM-D ratings. improved rating changes i n general were found to be negatively related to slow (delta and theta) wav e activity and positively related to fast (beta) activity at frontal record ing sites. Findings are discussed in relation to the neurochemistry and neu robiology of depressive disorders.