Friederike Holze

Friederike Holze, PhD Student

Universtiy Hospital Basel

LSD dose response – a double-blind whithin-subjects cross-over study in healthy subjects


Lysergic acid diethylamide (LSD) is used recreationally and is undergoing a revival in psychiatric research on substance-assisted psychotherapy for different disorders such as anxiety and depression, and is investigated as treatment for cluster headache. Modern experimental studies documented marked changes in perception at a moderate (100 µg orally or 75 µg intravenously) or high (200 µg orally) dose of LSD in healthy volunteers. However, the subjective effects of lower doses such as 25 µg and 50 µg have not yet been investigated in modern studies using validated psychometric tools. It is unclear to what extend such doses produce subjective effects and if these effects are similar and relative weaker to the alterations in consciousness induced by higher doses. LSD dose-response studies are lacking. To investigate the dose-related qualitative differences in the response to LSD and its pharmacokinetics, we conducted a double-blind, within-subject, cross-over study with six treatment conditions including: 1) 25 µg LSD, 2) 50 µg LSD, 3) 100 µg LSD, 4) 200 µg LSD, 5) 200 µg LSD plus the 5-HT2A receptor blocker ketanserin and 6) placebo in 16 healthy subjects. We assessed acute subjective drug effects using visual analogue scales (VASs), the five-dimensions of altered states of conciousness (5D-ASC), and the Mystical Experience Questionnaire (MEQ). Furthermore, we assessed autonomic effects and plasma concentrations of LSD. This study provides controlled data on the dose-effect relationship of LSD and provides important information for dose selection in substance-assisted psychotherapy research.


Friederike Holze obtained her Masters Degree in Pharmacy at the University of Basel in 2016. After completing her Master studies she joined the Psychopharmacology Research Group at the University Hospital of Basel as PhD Student under the supervision of Matthias Liechti. Her research focuses on the pharmacology of psychoactive substances, in particular LSD.



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