None listed
Conditions
Interventions
Latin square randomisation of 3 condition arms:
1. 20 mg oral 2C-B (powder, dissolved in bitter lemon drink)
2. 15 mg oral psilocybin (powder, dissolved in bitter lemon drink)
3. 200 ml bitter lemon d
Sponsors
Maastricht University
Eligibility
Inclusion criteria
Inclusion criteria: 1. Previous experience with at least one psychedelic substance (e.g., psilocybin, LSD, DMT, ayahuasca, psilocybe fungi =1 times) but not within the past three months. 2. Aged between 18 and 40 years. 3. Free from medication (any drug prescribed for a medical indication). 4. The participant is, in the opinion of the investigator, generally healthy based on assessment of medical history, physical examination, vital signs, electrocardiogram (ECG), and the results of the haematology, clinical chemistry, urinalysis, serology, and other laboratory tests. 5. A resting pulse and heart rate (as read on the ECG) =51 bpm and =100 bpm. For participants in good physical condition, the lower limit is =45 bpm. 6. A resting systolic blood pressure =91 mmHg and =140 mmHg and a resting diastolic blood pressure =51 mmHg and =90 mmHg. 7. Clinical laboratory test values within clinical reference ranges at screening. Borderline values may be accepted if they are, in the opinion of the investigator, clinically insignificant. 8. Normal binocular visual acuity, corrected or uncorrected. 9. Absence of any major medical, endocrine and neurological condition, as determined by the medical history, medical examination, electrocardiogram and laboratory analyses (haematology, clinical chemistry, urinalysis, serology). 10. Normal weight, body mass index. 11. Written informed consent.
Exclusion criteria
Exclusion criteria: 1. Previous experience of serious side effects to psychedelic drugs (anxiety or panic attacks). 2. Use of medication (other than paracetamol). 3. History of drug addiction (determined by the medical questionnaire, drug questionnaire and medical examination). 4. Excessive alcohol consumption (>20 units a week). 5. Excessive smoking (>20 cigarettes a week). 6. Current or history of psychiatric disorder (determined by the medical questionnaire and medical examination). 7. Hypertension (diastolic >90 mmHg; systolic >140 mmHg). 8. Liver dysfunction (hepatitis, cirrhosis, cancer, biliary cholangitis, hemochromatosis, alcoholic liver disease, etc as determined by the medical examination). 10. Renal insufficiency (as indicated by the medical examination). 11. History of cardiac dysfunctions (arrhythmia, ischemic heart disease, etc). 12. Pregnancy or lactation. 13. For women: absence of reliable contraceptive measures. 14. fMRI contraindications (pacemakers, metal implants, claustrophobia, permanent eye makeup).
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Acute dosing day performance as assessed by the digit symbol substitution task. | — |
Secondary
| Measure | Time frame |
|---|---|
| 1. Acute cognition: Sustained attention as measured by the Psychomotor Vigilance Task on each dosing day at +2:35 h Sensorimotor function as measured by the Motor Screen Task on each dosing day at + 2:15 h Executive function as measured by the Tower of London on each dosing day at + 2:20 h Emotional memory encoding and recollection as measured by the Emotional Memory Task on each dosing day at +2:40h and +1 day follow-up at + 0:50 h Visuospatial memory encoding and recollection as assessed by the Spatial Memory Task on each dosing at day + 2:50 h and + 3: 25 h Cognitive tempo as assessed by Matching Familiar Figures task on each dosing day at + 3:30 h 2. Acute behaviour: Self-hood using Virtual Reality self-location task at +5 hours on each dosing day Cognitive and emotional empathy as assessed by the Multifaceted Empathy Test and Interpersonal Reactivity Index on each dosing day at + 4 h and +6 h respectively 3. Acute fMRI: Functional connectivity (within-network, between-network) as measured by resting-state fMRI at + 1:30 h GABA, glutamate concentrations as measured by magnetic resonance spectroscopy seed analysis at + 1:45 h Emotional regulation and processing as measured by Affective Misattribution Task at + 2 h. fMRI resting-state introspection profiling as measured by the Amsterdam Resting State Questionnaire (ARSQ) at + 2:10 h. 4. Acute pharmacokinetics and metabolomics: Metabolite and drug quantification measured using hourly blood samples at baseline, +1 to+6 h Metabolite and drug quantification measured using earwax samples at baseline, +1 to +6h 5. Acute subjective effects: Drug intensity as measured by intensity visual analogue scale and Bowdles visual analogue scale hourly (baseline, +1 - +6h) Mood as measured by the Profile of Mood States questionnaire hourly (baseline, +1 - +6h) Depersonalisation as measured by the Clinician Administered Dissociative States Scale hourly (baseline, +1 - +6h) 6. Acute retrospective effects: Altered states of cons | — |
Contacts
Public ContactPablo-Alexandre Mallaroni
Maastricht University
Outcome results
None listed