Assessing the effects of Lysergic acid diethylamide (LSD) microdosing in people experiencing depression (LSDDEP1)

Open-label, single-group Phase II pilot (n=20) testing sublingual LSD solution microdosing twice weekly for 8 weeks with a predefined titration (start 8 µg, +1 µg per dose, limits 5–15 µg; reduce by 3 µg if not tolerated). Adherence monitored via video-recorded dosing.

Primary outcomes: percentage of participants completing the dosing regimen (audit of case report files) and total MADRS score at 8 weeks. Assessments at baseline, 2, 4, 6 and 8 weeks.