This study is an open-label, single-arm, within-subjects design in individuals with
mild-moderate Major Depressive Disorder (MDD). All participants will receive a single dose of
25mg of psilocybin in a therapeutic setting. In order to investigate the effects of length of
time on SSRI therapy, 30 participants with varying lengths of time on SSRI therapy will be
enrolled, stratified into four groups:
- Group 1: ≤ 1 year
- Group 2: 1 to ≤ 5 years
- Group 3: 5 to ≤ 10 years
- Group 4: > 10 years