Wellness Monitoring for Major Depressive Disorder

Inclusion Criteria: * Meet DSM-V criteria for Major Depressive Episode (MDE) in MDD as determined by MINI. * MADRS total score of equal to or less than 14. * In the current MDE, patient must currently be responding to an antidepressant medication or a combination of treatments for MDD. * Willing and able to complete self-reported assessments via a study-specific smartphone (LogPad), including sufficient fluency in English. * Willing to wear GT9X Link, a wrist-worn device for the duration of the study. Exclusion Criteria: * Axis I diagnosis, other than MDD, that is considered the primary diagnosis. * Bipolar I or Bipolar II diagnosis (lifetime), MDD with psychotic features (lifetime), schizophrenia, or schizoaffective disorder. * Presence of a significant Axis II diagnosis (borderline, antisocial). * High suicidal risk, defined by clinician judgement. * History of drug or alcohol use, with severity of at least moderate or severe, according to DSM criteria, within 6 months before screening. * Presence of significant neurological disorders, head trauma, or other unstable medical conditions. * Received an investigational drug (including investigational vaccines) or used an invasive investigational medical device within 90 days before screening or is currently enrolled in an investigational study. * Has a condition for which, in the opinion of the investigator, participation would not be in the best interest of the subject (e.g. compromise well being) or that could prevent, limit, or confound the protocol-specified assessments. * Subject is an employee of the investigator or study site, with direct involvement in the proposed study or other studies under the direction of that investigator or study site, or is a family member of an employee or the investigator.