RE104 Safety and Efficacy Study in Postpartum Depression

Inclusion Criteria:

• Is ≤15 months postpartum at Screening.

• Meet DSM-5 criteria for postpartum depression (PPD): experiencing a major depressiveepisode that began at any time starting at the beginning of the second trimester (≥14 weeks) of pregnancy through 4 weeks post delivery.

• Has a Hamilton Depression Scale (HAM-D) total score meeting severity threshold atScreening and Baseline.

• Is not using any psychotropic medications or psychotherapy for 30 days prior toScreening, OR are on an already stable/established regimen of SSRIs or psychotherapyfor 30 days prior to Screening.

• Has ceased breastfeeding at Screening.

• Has a negative pregnancy test at Screening and Day 0 prior to study drugadministration.

Exclusion Criteria:

• History or active postpartum psychosis per Investigator assessment.

• History of treatment-resistant depression within the current postpartum depressiveepisode.

• Has a significant risk of suicide.

• Active or medical history of bipolar disorder, schizophrenia, schizoaffectivedisorder, psychotic disorder and/or borderline personality disorder, or first-degreefamily history of psychosis or bipolar disorder.

• Medically significant condition rendering unsuitability for the study .

• Has received electroconvulsive therapy (ECT) or transcranial magnetic stimulationwithin 90 days prior to Screening.

• Has used psychedelics such as psilocybin, ayahuasca, mescaline, or LSD (with theexception of cannabis) within 12 months prior to Screening.

• Has used or will need to use prohibited medications.