This study examined adult subjects ages 21–70 with MDD who had participated in one of four placebo-controlled antidepressant treatment trials conducted over four years in the UCLA Laboratory of Brain, Behavior, and Pharmacology (n = 121) and healthy control subjects who were recruited for a study of the effects of antidepressant medication on normal brain function (n = 37). All depression trials were of similar size, utilized comparable recruitment procedures and inclusion/exclusion criteria, and subjects among the four trials did not differ significantly with respect to age, gender, or symptom severity at intake, so that the data were pooled for these analyses. Healthy control subjects had no current or prior history of any psychiatric or neurologic disorder [57]. All subjects were recruited by community advertisement and were screened for eligibility using a standard clinical evaluation, a structured clinical interview (Structured Clinical Interview for Axis I DSM-IV Disorders – Patient Edition: SCID-I/P, version 2.0) [58], and the 17-item Hamilton Depression Rating Scale (HamD17) [59]. Depressed subjects had HamD17 scores ≥16 at entry. Exclusion criteria included psychotic symptoms, cluster A or B
