LSD-associated “Alice in Wonderland Syndrome”(AIWS): A Hallucinogen Persisting Perception Disorder (HPPD) Case Report

Introduction

Alice in Wonderland Syndrome (AIWS), also known as Todd's syndrome, is a perceptual disorder primarily involving complex visual distortions. The syndrome is commonly described in relation to four core visual illusions: macropsia (objects perceived larger than they are), micropsia (objects perceived smaller), pelopsia (objects perceived nearer), and teleopsia (objects perceived farther away). Earlier literature has associated AIWS with a range of medical conditions including migraine and focal epilepsy, and transient AIWS-like phenomena have been reported during intoxication with hallucinogens such as LSD, but persistent AIWS after cessation of LSD—i.e. as part of Hallucinogen Persisting Perception Disorder (HPPD)—had not been documented in the professional literature prior to this report. Todd and colleagues present a clinical case intended to fill that gap: a single-patient case report of a young man who developed AIWS-type visual distortions associated with LSD use that persisted after he stopped taking the drug, consistent with HPPD as defined in DSM-5. The report aims to describe the clinical presentation, investigations, course and the authors' speculative mechanistic considerations regarding this apparently reversible phenomenon.