Sex, Hormones and Gamma-Aminobutyric Acid (GABA) in Stress Induced Anhedonia in Depression

Inclusion Criteria for all participants. * Males and females aged 18 through 25 * Capable of providing written informed consent, and fluent in English * Right-handed * Absence of any psychotropic medications for at least 2 weeks * Female subjects will be scheduled to participate during the follicular phase of their menstrual cycle Inclusion Criteria for "Current MDD" group: * Meets inclusion criteria for all subjects, plus: * Meets diagnostic criteria for a current episode of Major Depressive Disorder (MDD), as defined by the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). Inclusion Criteria for "Remitted MDD" group: * Meets inclusion criteria for all subjects, plus: * History of MDD as defined by DSM-5, but in remission for the past two months * Absence of anxiety disorder for the past two months Exclusion Criteria for all participants: * History of psychiatric illnesses, other than depression or anxiety disorders among the Current MDD and Remitted MDD groups. * History of psychotic episodes, suicidal ideation, or of electroconvulsive therapy (ECT) treatment * Use of hormone replacement therapy, or of anabolic steroids. * Use of hormonal contraceptives is permitted for female subjects only if the subject has regular menses * Failure to meet any MRI safety requirements * Serious or unstable medical illness, or history of neurological disease or damage * History of use of cocaine, stimulants, or dopaminergic drugs * History of substance use disorder or alcohol use disorder (as these terms are defined by DSM-5); except depressed subjects may have a history of 'Mild' substance/alcohol use disorder only if it ended as least 12 months ago.