Clinical TrialHealthy VolunteersLSDLSDPlaceboPlaceboRecruiting

Drug Effects on Mood and Behavior – Expectancy (MESA-X)

Early Phase I, randomised, placebo-controlled single-session study (n=48) testing a low (13 µg) dose of LSD versus placebo under known versus uncertain drug-identity instructions (balanced placebo design).

Target Enrollment
48 participants
Study Type
Phase I interventional
Design
Randomized, triple Blind

Detailed Description

This single-session, parallel-group balanced placebo study (N=48) examines pharmacological versus expectancy effects of a marginally detectable LSD dose (13 µg) in healthy volunteers.

Participants are randomised to one of four conditions (Known-Drug; Known-Placebo; Uncertain-Drug; Uncertain-Placebo) and attend a single 4-hour laboratory session; outcomes include subjective and behavioural responses to drug and expectancy manipulations.

The design separates pharmacological effects of microdose LSD from expectancy-driven effects to better understand microdosing claims.

Study Protocol

Preparation

sessions

Dosing

1 sessions
240 min each

Integration

sessions

Study Arms & Interventions

LSD (known)

experimental

LSD (13 µg) in tasteless solution; participants told they receive LSD.

Interventions

  • LSD13 µg
    via Oral• single dose

    LSD tartrate in tasteless solution (0.13 mL).

LSD (uncertain)

active comparator

LSD (13 µg) in tasteless solution; participants told they might receive stimulant, sedative, low-dose hallucinogen, or placebo.

Interventions

  • LSD13 µg
    via Oral• single dose

    LSD tartrate in tasteless solution (0.13 mL).

Placebo (known)

inactive

Placebo (distilled water); participants told they receive placebo.

Interventions

  • Placebo0.13 ml
    via Oral• single dose

    Distilled water (0.13 mL).

Placebo (uncertain)

inactive

Placebo (distilled water); participants told they might receive stimulant, sedative, low-dose hallucinogen, or placebo.

Interventions

  • Placebo0.13 ml
    via Oral• single dose

    Distilled water (0.13 mL).

Participants

Ages
18 – 40
Sexes
Male & Female

Inclusion Criteria

  • Inclusion Criteria:
  • English fluency
  • High school education or higher
  • BMI between 19-30 kg/m2

Exclusion Criteria

  • Exclusion Criteria:
  • Individuals with a medical condition contraindicating study participation as determined by the study physician (e.g., liver disease, abnormal EKG, liver or cardiovascular disease)
  • High blood pressure (>140/90)
  • Current suicidal ideation or suicide attempt in past 12 months
  • Past year severe substance use disorder
  • Personal or first-degree relative with history of psychosis
  • Currently taking any psychiatric medication (for conventional antidepressants must be off for ≥ 2 weeks)
  • Active panic disorder
  • Severe obsessive-compulsive disorder
  • Severe post-traumatic stress disorder
  • Women who are pregnant or planning to become pregnant

Study Details

  • Status
    Recruiting
  • Phase
    Phase I
  • Type
    interventional
  • Design
    Randomizedtriple Blind
  • Target Enrollment48 participants
  • Timeline
    Start: 2025-06-26
    End: 2026-06-05
  • Compounds
    LSDLSDPlaceboPlacebo
  • Topic
    Healthy Volunteers

Locations

University of Chicago — Chicago, Illinois, United States

Your Library