Seventy-nine healthy control participants and 65 individuals with MDD were recruited from the greater Boston area. Additionally, data from a smaller subsample of 30 individuals with rMDD were used in secondary analyses. All participants were right-handed, aged 18–65, had no history of neurological conditions, head injury, or seizures, and were free from recreational substances as indicated by a negative urine drug screen on the day of testing (Amedicheck CLIA-Waved 12-panel cup; Branan Medical Corporation, Irvine, California). Control participants were eligible if they had no lifetime DSM-IV diagnoses, no first-degree relatives with psychiatric illnesses, had a Beck Depression Inventory-II [BDI-II; 27] score < 13 and no lifetime use of psychotropic medication. MDD participants were eligible if they had a current MDD diagnosis according to the Structured Clinical Interview for DSM-IV [SCID-IV; 28], had been on stable antidepressant medication over the past 8 weeks or had taken no psychotropic medication for at least 2 weeks (drug-specific washout periods were applied), and had MDD as their primary diagnosis. rMDD subjects were required to have had at least one major depressive episode (MDE) in
