Does Psilocybin Require Psychedelic Effects to Treat Depression?

The psilocybin used in this study meets quality specifications suitable for human research use. The active drug is encapsulated using a hydroxypropyl methylcellulose (HPMC) capsule and contains 25 mg of psilocybin. The psilocybin will be administered once during the trial in combination with either risperidone 1 mg or place. It will also be administered in conjunction with supportive therapy.

The risperidone is encapsulated using a cellulose capsule and contains 1 mg of risperidone. The risperidone will be administered once during the trial in combination with either psilocybin 25 mg or placebo. It will also be administered with supportive therapy.

The placebo will be administered once during the trial in combination with either risperidone 1 mg or psilocybin 25 mg.