The purpose of this study is to examine the mood stabilizing and antipsychotic properties of
quetiapine in the treatment of depression by comparing subjects who were randomly assigned to
either quetiapine monotherapy, quetiapine and citalopram; or haloperidol and citalopram. We
hypothesize that quetiapine monotherapy would have similar effects to the combination of a
first generation antipsychotic plus an antidepressant for the treatment of a major depressive
episode with psychosis.