 Individuals with co-morbid panic disorder were excluded, since they may poorly tolerate typical starting doses of antidepressants , and individuals with co-morbid post-traumatic stress disorder were excluded, since they may have neuroendocrine regulatory responses different from those of depressed subjects without PTSD. Exclusion criteria for both groups included recent within 6 months alcohol or drug abuse as defined by DSM-IV criteria, concurrent psychotherapeutic interventions, poor medical health or abnormal clinical labs, active suicidality, and use of medications that could interfere with the study. 