Case report: Prolonged amelioration of mild red-green color vision deficiency following psilocybin mushroom use
This case report describes a person with mild red–green colour vision deficiency (deuteranomaly) who showed partial objective improvement on self‑administered Ishihara testing after ingesting 5 g dried psilocybin mushrooms, with peak effect at eight days and persistence for at least 16 days. The authors suggest a single psilocybin exposure may produce sustained post‑acute improvements in colour discrimination and call for systematic studies to confirm, generalise and elucidate the mechanism.
Authors
- Peter Hendricks
- Brian Barnett
Published
Abstract
Background
Recent survey data indicate that some people report long-term improvement in color vision deficiency (CVD), also known as color blindness, following use of psychedelics such as lysergic acid diethylamide (LSD) and psilocybin. However, there are no objective data reported in the medical literature quantifying the degree or duration of CVD improvement associated with psychedelic use. Case presentation Here we present the case of a subject with red-green CVD (mild deuteranomalia) who self-administered the Ishihara Test to quantify the degree and duration of CVD improvement following the use of 5 g of dried psilocybin mushrooms. Self-reported Ishihara Test data from the subject revealed partial improvement in CVD peaking at 8 days and persisting for at least 16 days post-psilocybin administration. This improvement may have lasted longer, though the subsequent observations are confounded by additional substance use.
Conclusion
A single use of psilocybin may produce partial improvements in CVD extending beyond the period of acute effect, despite this condition typically resulting from a genetic defect. Systematic exploration of this possible phenomenon is needed to confirm our findings, gauge their generalizability, and determine the mechanism of action.
Research Summary of 'Case report: Prolonged amelioration of mild red-green color vision deficiency following psilocybin mushroom use'
Introduction
Colour vision depends on three classes of cone photoreceptors (red, green, blue) and red–green colour vision deficiency (CVD) typically arises from X-linked mutations affecting the red or green cone photopigments. Management options are currently limited and experimental approaches such as gene, pharmacological, and stem cell therapies are under investigation. Previous survey data from the Global Drug Survey reported that some people with CVD subjectively experience durable improvement in their symptoms following use of psychedelics such as LSD or psilocybin, with a substantial minority reporting effects that last days to years—well beyond the acute pharmacological window. This paper presents a single-subject case aimed at providing objective, quantified data on this phenomenon. Barnett and colleagues report a self-experiment in which a man with mild deuteranomalous red–green CVD repeatedly self-administered the Ishihara Test before and after taking a 5 g dose of dried psilocybin mushrooms, with the intent of measuring any change in colour vision and its duration. The report aims to document the degree and temporal profile of any improvement and to note limitations that would guide future systematic study.
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Study Details
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- APA Citation
Barnett, B. S., Sweat, N. W., & Hendricks, P. S. (2023). Case report: Prolonged amelioration of mild red-green color vision deficiency following psilocybin mushroom use. Drug Science, Policy and Law, 9. https://doi.org/10.1177/20503245231172536
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