Predictors of Relapse in Major Depressive Disorder (PERFORM-D)

Inclusion Criteria: * Outpatients 18 to 70 years of age. * Meet DSM-V criteria for MDD as determined by the SCID-5 or other standardized clinical interviews. * In the current or most recent MDE, participant must be responding or responded to a treatment or a combination of treatments for MDD. Patients with remitted MDD who are currently not taking medications will also be accepted. Patients must have achieved remission at or later than May 1, 2023. * Participants must have a MADRS total score ≤14. * Participant must be willing and able to complete self-reported assessments including sufficient fluency in English. * Participant must be willing to wear the wrist-worn actigraphic device for the duration of the study. Exclusion Criteria: * Bipolar I or Bipolar-II diagnosis (lifetime), schizophrenia, or schizoaffective disorder. * Elevated risk of suicide, as determined by clinical evaluation. * Existence of major neurological disorders, head injury (if accompanied by any of \[A\] loss of consciousness longer than 24 hours, \[B\] documented evidence of Glasgow Coma Scale \<9 at the time of injury, \[C\] post-traumatic amnesia lasting longer than 24 hours) (43), or other unstable medical conditions. * The participant presents with any condition which, according to the researcher's judgment, could interfere with the assessments stipulated in the protocol. * The participant is employed by the researcher, actively involved in the current study or other research overseen by the same researcher, or is a relative of a study employee or the researcher.