subjects whose depressive symptoms have not remitted during their participation in the "pharmacokinetics and pharmacodynamics of citalopram and escitalopram" study or the "pharmacokinetics and pharmacodynamics of duloxetine" study

must be able to continue to take same dose of duloxetine through the course of the study

a history of failure for respond to electroconvulsive therapy (ect)

any metal in the head (except in mouth)

implanted medication pump or cardiac pacemaker

have had prior brain surgery

have unprovoked seizure disorder or family history of treatment resistant epilepsy

pregnancy

psychiatric hospitalization within the past two weeks

suicide attempt with hospitalization within past three months