Characterization of Altered Waking States of Consciousness in Healthy Humans

NCT03853577 | Completed

• 1 other identifier: PSICON-132
• Study Type: interventional
• Target: 25
• Locations: 1 country
• Sites: 1

Brief Summary

Altered waking states of consciousness and its underlying functional organization have gained increasing interest in recent years, i.e. in identifying the neural basis of consciousness. To overcome fundamental shortcomings of current methods to objectively assess the level of consciousness, the investigators propose here to apply a novel and empirically validated measure called 'perturbational complexity index' (PCI) based on the integrated information theory (IIT). This involves a combination of transcranial magnetic stimulation (TMS) and highdensity electroencephalography (hd-EEG) to measure electrocortical responses as distributed cerebral interactions ('integration') and spatiotemporal pattern ('information'). Given the finding of subjectively expanded consciousness as induced here by psilocybin, the investigators hypothesize that the PCI may be higher in such states. This will be the first TMS/hd-EEG study to investigate quantitatively the level of consciousness in a pharmacologically altered waking state of consciousness.

Conditions

Altered Waking States of Consciousness in Healthy Humans

Outcome Measures

Primary Outcomes (1)

• Assessment of change of the 'perturbational complexity index' (PCI) in psilocybin compared to placebo condition in healthy humans as indexed by TMS/EEG respones

  Application of navigated TMS/EEG over the premotor cortex (Brodmann-Area BA06), the midline sensorimotor cortex (BA04) and the superior occipital gyrus/cuneus (BA19)

  First investigational visit at week 1, second investigational visit at week 3

Secondary Outcomes (6)

• Assessment of change of the learning rate in a probabilistic learning task in psilocybin compared to placebo condition

  First investigational visit at week 1, second investigational visit at week 3

• Assessment of change of the effect of psilocybin compared to placebo condition on all frequency bands of resting state EEG

  First investigational visit at week 1, second investigational visit at week 3

• Psychometric assessment of change of the sense of self, of perceptual alterations and of mood in psilocybin compared to placebo condition (1)

  First investigational visit at week 1, second investigational visit at week 3

• Psychometric assessment of change of the sense of self, of perceptual alterations and of mood in psilocybin compared to placebo condition (2)

  First investigational visit at week 1, second investigational visit at week 3

• Psychometric assessment of change of the sense of self, of perceptual alterations and of mood in psilocybin compared to placebo condition (3)

  First investigational visit at week 1, second investigational visit at week 3

Study Arms (2)

Psilocybin

ACTIVE COMPARATOR

Other: TMS/EEG

Placebo

PLACEBO COMPARATOR

Other: TMS/EEG

Interventions

TMS/EEG OTHER

navigated TMS/high-density(hd)-EEG to directly stimulate defined cortical areas and investigate quantitatively the level of consciousness in psilocybin-induced altered brain states

Placebo; Psilocybin

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Healthy male or female volunteers aged 18-40 years

You may not qualify if:

• Personal and family history of major psychiatric disease (e.g. major depression, bipolar disorder, psychotic disorder) as defined in the DSM-V
• Any major medical condition (e.g. neurologic, cardiovascular, metabolic disease), family history of seizure disorder
• Current psychopharmacological treatment / use of medication
• Pregnant or breastfeeding women

Sponsors & Collaborators

• University of Zurich: lead

Study Sites (1)

Psychiatrische Universitätsklinik Zürich

Zurich, 8032, Switzerland

Location

Related Publications (1)

• Ip CT, Olbrich S, de Bardeci M, Monn A, Ort A, Smallridge JW, Vollenweider F. Psilocybin-induced alterations in EEG power, connectivity and network dynamics in healthy subjects: Correlations with subjective experience and implications for therapeutic applications. Prog Neuropsychopharmacol Biol Psychiatry. 2026 Jan 27:111626. doi: 10.1016/j.pnpbp.2026.111626. Online ahead of print.

  PMID: 41611012 DERIVED

Study Officials

• Franz X. Vollenweider, Prof, MD

  Psychiatric Hospital, University of Zurich

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: January 10, 2019
• First Posted: February 25, 2019
• Study Start: July 8, 2020
• Primary Completion: April 25, 2021
• Study Completion: April 25, 2021
• Last Updated: April 29, 2021

Record last verified: 2020-04

Locations

CH (1)