Study Purpose: This study aims to see if a single dose of a medicine called RE104 can help reduce depressive symptoms in women with postpartum depression. Postpartum depression is a type of depression that some mothers experience after giving birth.

Eligibility: To be part of this study, women must be within 12 months of giving birth and have postpartum depression that started during or after the second trimester of pregnancy. They should not be using any new mental health medications or treatments for at least 30 days before the study, unless they have been on a stable treatment of SSRIs (a type of depression medication) or therapy. Participants must also have stopped breastfeeding and have a negative pregnancy test.

Exclusion Criteria: Women cannot participate if they have had postpartum psychosis, treatment-resistant depression, or any serious mental health disorders like bipolar disorder or schizophrenia. Other exclusions include significant risk of suicide, recent electroconvulsive therapy, or use of psychedelics other than cannabis within the past year.

• Study involves one dose of RE104.
• Participants must be available for study visits and follow-ups.
• Potential risks include side effects from the study drug.