Adults between the ages of 21 and 55, with or without major depression as diagnosed with The Structured Clinical Interview of Diagnosis (SCID) of the Diagnostic and Statistical Manual of Mental Disorder, Fourth Edition (DSM-IV), will be recruited. All depressed patients will be included, although we will characterize patients a priori as having a predominantly melancholic, atypical, or mixed symptom pattern. We plan to recruit at least 20 patients in each group.