Schizophrenia Bulletin
August 5, 2020
Pantelis Leptourgos, Martin Fortier-Davy, Robin Carhart‐Harris et al.
88 citations
A multidisciplinary working group reviewed evidence on the similarities and differences between hallucinations induced by psychedelics and those occurring in schizophrenia-spectrum disorders, examining data from pharmacology, brain imaging, phenomenology, and anthropology. The authors highlight both shared features and distinct characteristics across these scales, and attempt to integrate findings using computational approaches. They conclude with recommendations for future research, emphasizing the need for further study to clarify the relationship between these types of hallucinations.
Schizophrenia Bulletin
August 8, 2018
T. M. Luhrmann, Ben Alderson‐day, Vaughan Bell et al.
74 citations
Trauma can contribute to voice-hearing but is not necessary for it. This article uses ethnographic and other data to show multiple pathways to voice-hearing in both clinical and nonclinical populations, excluding known causes like drugs or epilepsy. Trauma sometimes plays a major role, sometimes a minor role, and sometimes no role at all. Distinct phenomenological patterns in voice-hearing may reflect different salience of trauma for those who hear voices.
BJPsych open
July 25, 2022
Deborah Wearne, Jeremiah Ayalde, Guy Curtis et al.
10 citations
Visual hallucinations in people with PTSD can be indistinguishable from those in schizophrenia. A study comparing three groups who hear voices—schizophrenia without trauma history (19 participants), PTSD with dissociation (17 participants), and comorbid schizophrenia and PTSD (20 participants)—found remarkable similarity in visual experiences, including rates of complex visual hallucinations, across all groups. No significant differences emerged in the severity or components of distress surrounding these experiences. Dissociation predicted visual hallucination severity only for the comorbid group, not for PTSD or schizophrenia alone. Multimodal hallucinations were frequent in both schizophrenia and PTSD. The authors suggest a model for visual hallucinations in PTSD following two separate neurobiological pathways based on distinct trauma responses.
Schizophrenia Bulletin
April 17, 2025
Nathan H. Heller, Frederick S. Barrett, Tobias Buchborn et al.
3 citations
Visual hallucinations in Lewy body diseases (Parkinson's disease and dementia with Lewy bodies) and those induced by serotonergic psychedelics (psilocybin, mescaline) share overlapping phenomenology and neural mechanisms, despite different underlying causes. Both conditions produce visual aberrations from minor distortions to complex hallucinations, including illusory motion and entity encounters. Neuroimaging shows a common pattern of overactive associative cortex and underactive sensory cortex. Serotonin 2A receptor modulation is involved in both: psychedelics act through 5-HT2A and 5-HT1A receptors, while in Lewy body diseases, 5-HT2A receptor upregulation correlates with increased hallucinations, and blocking it with pimavanserin reduces them. Shared cortical signatures include reduced visual evoked responses and shifts toward visual excitation.
Psychiatry research
January 1, 2023
Flavie Waters
1 citation
Hallucinations are among the least understood human experiences, recognized across cultures and in both mental illness and those not mentally unwell. Early research on hallucinogens like LSD was criticized and withdrawn, but its revival offers new opportunities to examine the mechanism of hallucinating. Studying psychedelic compounds in controlled settings with mentally healthy individuals may reveal temporal shifts in perceptual awareness, decode what influences contents, affect, meaning, and appraisals of hallucinations, and guide novel psychotherapy and drug therapy.