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The primary objective of this study is to determine whether equivalent moderately high doses of LSD, psilocybin, and DMT produce qualitatively similar peak effects when the effect duration is standardized with ketanserin. A DMT infusion mimicking oral LSD and psilocybin administrations will be tested, as well as intravenously administered ketanserin.
Lysergic acid diethylamide (LSD), psilocybin, and N,N-dimethyltryptamine (DMT) are serotonergic hallucinogens (psychedelics) and currently investigated as therapeutic tools for the treatment of various psychiatric disorders. They are usually administered in a dose range which induces an alteration of consciousness via the stimulation of the serotonin (5-HT)2A receptor. However, there are differences in the receptor activation profiles between the three substances that may induce different subjective effects. Moreover, they exhibit different pharmacokinetic qualities. In comparative studies of LSD and psilocybin blinding was impaired by the different duration of subjective effects. This study aims to ensure blinding by ending all experiences at the same time with the 5HT2A antagonist ketanserin. Moreover, no study has yet directly compared DMT to LSD and psilocybin. The DMT infusion will be modeled in accordance with the course of an oral LSD and psilocybin administration. Therefore, the LPD-study compares the acute and subacute effects of LSD, psilocybin, and DMT while standardizing the time course and the duration of action for all substances.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| LSD | Experimental | 150 µg lysergic acid diethylamide followed by 20 mg ketanserin intravenously after 3 h |
|
| Psilocybin | Experimental | 30 mg Psilocybin followed by 20 mg ketanserin intravenously after 3 h |
|
| DMT | Experimental | Dose escalating DMT intravenous infusion up to 2 mg/min followed by 20 mg ketanserin intravenously after 3 h |
|
| Placebo | Placebo Comparator | Placebo followed by 20 mg ketanserin intravenously after 3 h |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| LSD | Drug | A moderate to high oral dose of 150 µg LSD will be administered followed by 20 mg intravenous ketanserin after 3 h |
|
| Measure | Description | Time Frame |
|---|---|---|
| 1. Altered state of consciousness profile (5D-ASC) | 5 Dimensions of Altered States of Consciousness (5D-ASC) consisting of 94 items to be rated on a visual analog scale (0-100 mm), with higher values indicating stronger effects. | 18 months |
| Measure | Description | Time Frame |
|---|---|---|
| Subjective effects (VASs) | Visual Analog Scales assessing the intensity and duration of subjective effects on a scale from 0 - 100 percent with higher scores representing more intense effects. | 18 months |
| Mystical-type experiences (PES) |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Role | Phone | Extension | |
|---|---|---|---|---|
| Matthias E Liechti, Prof. Dr. MD | Contact | 61 328 68 68 | +41 | matthias.liechti@usb.ch |
| Mélusine Humbert-Droz, MSc | Contact | 61 328 48 19 | +41 | melusine.humbert-droz@usb.ch |
| Name | Affiliation | Role |
|---|---|---|
| Matthias E Liechti, Prof. Dr. MD | University Hospital, Basel, Switzerland | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| University Hospital | Recruiting | Basel | 4056 | Switzerland |
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| ID | Term |
|---|---|
| D008238 | Lysergic Acid Diethylamide |
| D011562 | Psilocybin |
| ID | Term |
|---|---|
| D008237 | Lysergic Acid |
| D004873 | Ergolines |
| D004876 | Ergot Alkaloids |
| D000470 | Alkaloids |
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4-period, random order, placebo-controlled, double-blind cross-over study
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| Psilocybin | Drug | A moderate to high oral dose of 30 mg psilocybin will be administered followed by 20 mg intravenous ketanserin after 3 h |
|
| DMT | Drug | A moderate to high, dose-escalating, intravenous infusion up to 2 mg/min DMT will be administered followed by 20 mg intravenous ketanserin after 3 h |
|
| Placebo | Drug | An oral and an intravenous placebo will be administered followed by 20 mg intravenous ketanserin after 3 h |
|
This 100-item Psychedelic Experience Questionnaire/Scale (PES100) is rated on a six-point scale (0 indicating "not at all" and 5 indicatin "extremely"). It comprises distractor items as well as subscales which measure mystical-type effects.
| 18 months |
| Mystical-type experiences (PAE-PS-ext) | This Phenomenological-Autobiographical-Existential Psychedelic Scale extended (PAE-PS-ext) questionnaire rates psychedelic experiences with a focus on phenomenological, autobiographical, and existential psychedelic experiences (scale from 0 - 100 percent with higher scores representing more intense effects). | 18 months |
| 3. Emotional breakthrough inventory (EBI+) | This 18-item questionnaire is a visual analog scale (from 0 - 100 percent with higher scores representing more intense effects) assessing emotional breakthrough throughout the study sessions. | 18 months |
| Plasma levels of LSD | Assessed 20 times on each study day via blood samples | 18 months |
| Plasma levels of psilocybin | Assessed 20 times on each study day via blood samples | 18 months |
| Plasma levels of DMT | Assessed 20 times on each study day via blood samples | 18 months |
| Plasma levels of ketanserin | Assessed 20 times on each study day via blood samples | 18 months |
| Plasma levels of oxytocin | Assessed 2 times on each study day via blood samples | 18 months |
| Plasma levels of prolactin | Assessed 2 times on each study day via blood samples | 18 months |
| Plasma levels of cortisol | Assessed 2 times on each study day via blood samples | 18 months |
| Autonomic effects I | Assessed 16 times on each study day via systolic and diastolic blood pressure | 18 months |
| Autonomic effects II | Assessed 16 times on each study day via heart rate | 18 months |
| Autonomic effects III | Assessed one time at screening visit and twice on each study day via ECG (QT-time) | 18 months |
| Adverse effects (B-LR) | The 2011 revised Beschwerden-Liste (B-LR) consists of a 40-item list covering a wide variety of symptoms and complaints that are answered with a four-point intensity-scoring ranging from 0 indicating "not at all" to 3 indicating "strong." | 18 months |
| Adverse effects (SPSI) | The Swiss Psychedelic Side Effects Inventory evaluates side effects associated with psychedelics using a binary "yes or no" approach. Severity is recorded using a three-point intensity scale ranging from 1 indicating "light" to 3 indicating "strong." The impact is recorded using a five-point scale ranging from -2 "very disadvantageous" to +2 "very advantageous." The relation to the drug is recorded using a five-point scale ranging from 0 indicating "unknown" to 4 indicating "certain." | 18 months |
| Adverse Events (AE) | Any report of adverse events will be recorded on a AE-Form. | 18 months |
| D006571 |
| Heterocyclic Compounds |
| D006576 | Heterocyclic Compounds, 4 or More Rings |
| D000072471 | Heterocyclic Compounds, Fused-Ring |
| D026121 | Indole Alkaloids |
| D007211 | Indoles |
| D006574 | Heterocyclic Compounds, 2-Ring |
| D014363 | Tryptamines |
| D054836 | Indolizidines |
| D007212 | Indolizines |