Psilocybin in Co-occuring Major Depressive Disorder and Borderline Personality Disorder

Inclusion Criteria: * Age 18-65 * Diagnosed with current major depressive disorder * Montgomery-Asberg Depression Rating Scale (MADRS) score of \> 20 * Diagnosed with borderline personality disorder * Borderline Personality Disorder Symptom Assessment Scale (BPD-SAS) score of \> 20 * Ability to understand and sign the consent form Exclusion Criteria: * Unstable medical illness based on history or clinically significant abnormalities on baseline physical examination * Current pregnancy or lactation, or inadequate contraception in women of childbearing potential * Illegal substance use based on urine toxicology screening (except cannabis use) * Current or past history of bipolar I disorder, schizophrenia, or schizoaffective disorder * Active substance use disorder