Neuroimaging & Brain MeasuresHealthy VolunteersMicrodosingLSD

Low-Dose LSD Alters Early and Late Event-Related Potentials to Emotional Faces

This double-blind, randomised, placebo-controlled study (n=39) examines the effects of a single low dose of LSD (26µg) on event-related potentials during an emotional face oddball task. It finds that LSD significantly reduced the amplitude of N170 ERP to neutral faces and P300 ERP to neutral and happy faces, suggesting differential effects on brain responses to social and emotional information.

Authors

  • Harriet de Wit
  • Richard Lee

Published

Psychedelic Medicine
individual Study

Abstract

Introduction

Despite widespread popular interest in the use of low doses of Lysergic acid diethylamide (LSD) to improve mood, little is known about how these doses affect emotional processing in the brain. In this study, we tested the effect of a single low dose of LSD (26 µg) compared with placebo on electroencephalogram (EEG) event-related potentials (ERP: N170, P300 and Mismatch Negativity) in healthy adults, while participants viewed angry, happy, and neutral faces. We hypothesized that the drug might affect either neutral faces, which are sometimes perceived as threatening, or emotional faces.

Methods

Healthy young adults (n = 39) received LSD (26 µg or placebo sublingually) before completing an oddball task with emotional facial expressions during EEG recording. The N170 and P300 evoked potentials were recorded using EEG. LSD and placebo were administered in double-blind, randomized order separated by at least 7 days. During the oddball task, three emotional faces were presented infrequently (angry, happy, neutral) in a block design, and a cartoon face was presented frequently.

Results

LSD significantly reduced the amplitude of the occipitotemporal N170 ERP to Neutral faces, but not angry or happy faces. LSD also reduced the amplitude of the midline posterior parietal P300 ERP to neutral and happy faces, but not angry faces.

Discussion

These differential effects of LSD on the amplitude of the N170 and P300 to neutral and emotional faces add to our understanding of how low doses of LSD might affect the brain response to social and emotional information.

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Research Summary of 'Low-Dose LSD Alters Early and Late Event-Related Potentials to Emotional Faces'

Introduction

Haggarty and colleagues situate this study within renewed scientific interest in LSD and growing popular use of very low ‘‘micro’’ doses, which proponents claim improve mood and cognition. Prior controlled studies have shown that single low doses (up to the doses used here) produce only mild subjective effects, yet imaging and connectivity studies suggest low doses can alter prefrontal–limbic and reward circuitry. The authors note that face‑processing paradigms and event‑related potentials (ERPs) such as the N170 and P300 provide a well‑established window onto how drugs alter social and emotional information processing, and that previous work with full and subhallucinogenic doses of psychedelics (psilocybin, LSD) has produced inconsistent effects on these ERPs. Mismatch Negativity (MMN) to deviant stimuli is also of interest given prior reports that LSD can blunt MMN to auditory deviants. The present study tested whether a single low sublingual dose of LSD tartrate (26 mg, within‑participant, double‑blind versus placebo) alters the N170, P300 and MMN elicited by angry, happy and neutral human faces presented infrequently in an oddball design with a frequent cartoon face. Based on prior findings and the hypothesis that neutral faces can be perceived as ambiguous or threatening, the investigators predicted that LSD would reduce responses to neutral faces, and additionally that LSD would dampen responses to angry but not happy faces.

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Study Details

References (23)

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