The purpose of this study is to see if psilocybin, an investigational drug, is safe and well
tolerated. Researchers also want to know if psilocybin can improve symptoms of depression.
This study will see if psilocybin is safe and well tolerated by tracking changes in suicidal
thoughts and behaviour, monitoring if any participants choose to stop participating in the
study, and measuring any serious side effects, as well as how long they take to resolve. This
study will also see if depression symptoms improve (or worsen) after psilocybin is
administered. Additional information about participants' depressive symptoms and side effects
will also be measured during the study.