Knowra Hallucinogen persisting perception disorder Hallucinogen persisting perception disorder Hallucinogen persisting perception disorder (HPPD) is a condition in which perceptual disturbances associated with hallucinogen intoxication recur or persist after acute drug effects have ended.
Visual snow syndrome : A neurological condition marked by continuous visual static and sometimes additional visual symptoms. Its persistent static resembles one HPPD symptom, but it can occur without hallucinogen exposure.
Hallucinogens : Psychoactive substances that can produce profound changes in perception, thought, and mood. HPPD is defined by perceptual disturbances linked to prior hallucinogen intoxication.
Differential diagnosis : The process of distinguishing a condition from other disorders with similar signs or symptoms. Clinicians assess other neurological, ophthalmological, psychiatric, and substance-related explanations for visual symptoms.
Visual snow : A perception of innumerable flickering dots across the visual field, often compared to television static. This is a frequently reported HPPD disturbance, though it also occurs independently.
Palinopsia : A visual disturbance in which images persist or recur after the stimulus has disappeared. Afterimages and trailing images are among the visual effects reported in HPPD.
Psychedelic experience : An altered state of consciousness that may involve changes in perception, emotion, and thought. HPPD symptoms resemble aspects of an acute psychedelic experience but outlast its drug effects.
Clinical interview : A structured or semi-structured conversation used to gather information about symptoms and health history. A history of substance exposure and symptom timing helps establish whether HPPD fits.
Trailing phenomenon : The perception that a moving object leaves a brief visual trail behind it. Trails can recur after intoxication as one recognizable HPPD symptom.
Entoptic phenomena : Visual perceptions originating within the eye, such as floaters or blue-field entoptic phenomenon. HPPD can heighten awareness of visual effects that arise within the eye.
Drug intoxication : A temporary state of altered mental or physical functioning caused by a psychoactive substance. HPPD distinguishes persistent or recurrent disturbances from effects confined to intoxication.
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