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On Perception and Consciousness in HPPD: A Systematic Review
Pieter J Vis1,2,3, Anneke E Goudriaan2,4, Bastiaan C Ter Meulen5
1Department of Neurology, Zaans Medical Centre, Zaandam, Netherlands.
Frontiers in Neuroscience
|August 30, 2021
Summary
Hallucinogen-persisting perception disorder (HPPD) involves diverse perceptual symptoms beyond current diagnostic criteria. Co-occurring depression can worsen HPPD persistence and treatment outcomes.
Area of Science:
- Psychiatry
- Neuroscience
- Psychopharmacology
Background:
- Hallucinogen-persisting perception disorder (HPPD) is a recognized diagnostic category, yet its perceptual phenomenology and consciousness changes during flashbacks remain poorly understood.
- Current diagnostic criteria in the DSM-5 may not fully encompass the spectrum of HPPD symptoms.
Approach:
- Systematic evaluation of 66 original case reports and case series detailing 97 individuals with HPPD.
- Analysis focused on defining the phenomenology, associated psychopathology, and clinical course of the disorder.
Key Points:
- Identified 64 unique HPPD symptoms, with 76% resembling Alice in Wonderland syndrome.
- Over 50% of symptoms were non-visual, and 38% were perceptual symptoms unrelated to prior intoxication states.
- Co-occurring depression (with or without anxiety) was linked to longer HPPD symptom duration and poorer treatment outcomes.
Conclusions:
- HPPD is characterized by alterations in the content of consciousness and a shift in attention towards endogenous phenomena, differing from acute psychedelic intoxication states.
- The study suggests expanding HPPD diagnostic criteria beyond current DSM-5 limitations.
- Recommendations are provided for clinical practice and future research directions.
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