Shortened LSD Intervention for Major Depressive Disorder

This study will administer open-label oral LSD hemi-L-tartrate 250 µg followed 45 minutes later by oral risperidone 1 mg to 10 participants with Major Depressive Disorder (MDD) for a pilot investigation into the effects of abbreviated LSD on depression. Participants will be monitored for 10.5 hours and assessed for subjective effects and discharge readiness at several time points following the dose. The main aim of this study is to test whether risperidone can be used to abbreviate the subjective effects of LSD, and whether this abbreviated LSD experience will have any potential therapeutic benefit in patients with MDD.