Can your phone predict postpartum depression treatment success?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * At least 18 years of age * Able to read and communicate in English * Between 28 weeks pregnant and 12 weeks postpartum * Moderate-to-severe depression, as defined by Edinburgh Postnatal Depression Scale (EPDS) score ≥11 * Not currently seeing a provider for mental health care * Own functioning iOS smartphone (iPhone 11 or newer, iOS 18 or newer) with access to reliable data plan and Wifi) * Able to read and understand a written informed consent form * Willingness to participate in treatment through the study and follow all study procedures, including providing HIPAA Authorization for research, installing a study app on personal iPhone, and wearing the provided Apple Watch for at least 20 hours every day in the first four weeks of the study (including while sleeping) Exclusion Criteria: * Currently receiving treatment by a therapist or a psychiatrist * Unstable suicidality (e.g., 2 or more suicide attempts or self-injurious behaviors resulting in hospitalization in the last 6 months) * Current substance use disorder that interferes with treatment: specifically, patients meeting diagnostic criteria for Substance Use Disorder (SUD) will be eligible for inclusion only if they are able to attend sessions while not under the influence of that substance, with the exception of individuals abusing opiates or freebase cocaine, who will be excluded * Principal diagnosis of psychosis unrelated to depression (unipolar or bipolar) * Neurological conditions * Severe uncontrolled medical conditions (e.g., anorexia nervosa, cardiac conditions requiring continuous monitoring) * Cognitive impairment (e.g., developmental disability, dementia) * Previously participated in the UCLA Depression Grand Challenge "New Moms Mood Tracking \& Wellbeing Study" (IRB #20-001924)