Visual hallucinations in psychosis explained

Visual hallucinations in psychosis is when a subject with psychosis endures visual experiences which occur in the absence of corresponding external stimulation of the eye in the awake state, in which the subjects do not feel like they have control over, with sufficient sense of reality to resemble a authentic visual perception.

Approximately one-third of patients with a psychotic disorder experience visual hallucinations.[1] The mechanism behind this is largely unknown.[1] This slows development of new theraputic approaches.[1]

Presentation

Visual hallucinations in psychosis are reported to have physical properties similar to real perceptions.[2] They are often life-sized, detailed, and solid, and are projected into the external world. They typically appear anchored in external space, just beyond the reach of individuals, or further away. They can have three-dimensional shapes, with depth and shadows, and distinct edges. They can be colorful or in black and white and can be static or have movement.[3] [4] [5] [6] [7] [8]

Simple vs. complex

Visual hallucinations may be simple/non-formed visual hallucinations, or complex/formed visual hallucinations.[9]

Simple visual hallucinations without structure are known as phosphenes and those with geometric structure are known as photopsias. These hallucinations are caused by irritation to the primary visual cortex (Brodmann's area 17).[10]

Sometimes, hallucinations are 'Lilliputian', i.e., patients experience visual hallucinations where there are miniature people, often undertaking unusual actions. Lilliputian hallucinations may be accompanied by wonder, rather than terror.[11]

Most people have multiple VH types.[2] Complex VH were most prevalent, mainly consisting of people and animals, followed by simple, then geometric VH. Few patients experienced only simple VH.

Content

The frequency of hallucinations varies widely from rare to frequent, as does duration (seconds to minutes). It is common that the visual hallucinations typically occurred daily, for afew minutes per episode.[12] The content of hallucinations varies as well. Preliminary research has found that most individuals had multiple types of visual hallucinations.[12] Scenes involving people and/or animals were the most common, followed by simple geometric images.[2]

Complex (formed) visual hallucinations are more common than Simple (non-formed) visual hallucinations.[5] [7] In contrast to hallucinations experienced in organic conditions, hallucinations experienced as symptoms of psychoses tend to be more frightening. An example of this would be hallucinations that have imagery of bugs, dogs, snakes, distorted faces. Visual hallucinations may also be present in those with Parkinson's, where visions of dead individuals can be present. In psychoses, this is relatively rare, although visions of God, angels, the devil, saints, and fairies are common.[6] [7] Individuals often report being surprised when hallucinations occur and are generally helpless to change or stop them.[4] In general, individuals believe that visions are experienced only by themselves.[4] [5]

Primary Visual Cortex

V1's functional connection with other brain regions is reduced in psychotic patients who experience visual hallucinations.[1] This contrasts with the expectation that V1 would be active during conscious visual perception.[1]

Causes

Two neurotransmitters are particularly important in visual hallucinations – serotonin and acetylcholine. They are concentrated in the visual thalamic nuclei and visual cortex.[13]

The similarity of visual hallucinations that stem from diverse conditions suggest a common pathway for visual hallucinations. Three pathophysiologic mechanisms are thought to explain this.

The first mechanism has to do with cortical centers responsible for visual processing. Irritation of visual association cortices (Brodmann's areas 18 and 19) cause complex visual hallucinations.[10] [14]

The second mechanism is deafferentation, the interruption or destruction of the afferent connections of nerve cells, of the visual system, caused by lesions, leading to the removal of normal inhibitory processes on cortical input to visual association areas, leading to complex hallucinations as a release phenomenon.[11] [14]

Prevalence

The DSM-V lists visual hallucinations as a primary diagnostic criterion for several psychotic disorders, including schizophrenia and schizoaffective disorder.[15] [16] Visual hallucinations can occur as a symptom of the above psychotic disorders in 24% to 72% of patients at some point in the course of their illness.[17] [18] [19]

Notes and References

  1. van Ommen . Marouska M . van Laar . Teus . Renken . Remco . Cornelissen . Frans W . Bruggeman . Richard . Visual Hallucinations in Psychosis: The Curious Absence of the Primary Visual Cortex . Schizophrenia Bulletin . 24 February 2023 . 49 . Supplement_1 . S68–S81 . 10.1093/schbul/sbac140 . 36840543 . 9960034 .
  2. van Ommen . M.M. . van Laar . T. . Cornelissen . F.W. . Bruggeman . R. . Visual hallucinations in psychosis . Psychiatry Research . October 2019 . 280 . 112517 . 10.1016/j.psychres.2019.112517 . 31446216 .
  3. Gauntlett-Gilbert . Jeremy . Kuipers . Elizabeth . Phenomenology of Visual Hallucinations in Psychiatric Conditions . The Journal of Nervous and Mental Disease . March 2003 . 191 . 3 . 203–205 . 10.1097/01.nmd.0000055084.01402.02 . 12637850 .
  4. Dudley . Robert . Wood . Markku . Spencer . Helen . Brabban . Alison . Mosimann . Urs P. . Collerton . Daniel . Identifying Specific Interpretations and Use of Safety Behaviours in People with Distressing Visual Hallucinations: An Exploratory Study . Behavioural and Cognitive Psychotherapy . May 2012 . 40 . 3 . 367–375 . 10.1017/S1352465811000750 . 22321567 .
  5. Bracha. H. Stefan . Wolkowitz . Owen M. . Lohr . James B. . Karson . Craig N. . Bigelow . Llewellyn B. . High prevalence of visual hallucinations in research subjects with chronic schizophrenia . American Journal of Psychiatry . April 1989 . 146 . 4 . 526–528 . 10.1176/ajp.146.4.526 . 2929755 .
  6. Lowe . Gordon R. . The Phenomenology of Hallucinations as an Aid to Differential Diagnosis . British Journal of Psychiatry . December 1973 . 123 . 577 . 621–633 . 10.1192/bjp.123.6.621 . 4772302 .
  7. Frieske . David A . Wilson . William P . Formal qualities of hallucinations: a comparative study of the visual hallucinations in patients with schizophrenic, organic, and affective psychoses . Proceedings of the Annual Meeting of the American Psychopathological Association . 1966 . 54 . 49–62 . 5951932 . 101011898 .
  8. Asaad . G . Shapiro . B . Hallucinations: theoretical and clinical overview . American Journal of Psychiatry . September 1986 . 143 . 9 . 1088–1097 . 10.1176/ajp.143.9.1088 . 2875662 .
  9. Book: 10.1016/B978-0-12-385157-4.00135-4 . Hallucinations, Visual and Auditory . Encyclopedia of the Neurological Sciences . 2014 . Fraser . J.A . 500–501 . 978-0-12-385158-1 .
  10. Price . John . Whitlock . F.A. . Hall . R.T. . The Psychiatry of Vertebro-Basilar Insufficiency with the Report of a Case . Psychopathology . 1983 . 16 . 1 . 26–44 . 10.1159/000283948 . 6844659 .
  11. Menon . G.Jayakrishna . Rahman . Imran . Menon . Sharmila J . Dutton . Gordon N . Complex Visual Hallucinations in the Visually Impaired . Survey of Ophthalmology . January 2003 . 48 . 1 . 58–72 . 10.1016/s0039-6257(02)00414-9 . 12559327 .
  12. Toh . Wei Lin . Thomas . Neil . Rossell . Susan Lee . The Phenomenology of Visual and Other Nonauditory Hallucinations in Affective and Nonaffective Psychosis: A Mixed Methods Analysis . Journal of Nervous & Mental Disease . April 2024 . 212 . 4 . 205–212 . 10.1097/NMD.0000000000001750 . 38090976 .
  13. Manford . Mark . Andermann . Frederick . Complex visual hallucinations. Clinical and neurobiological insights . Brain . October 1998 . 121 . 10 . 1819–1840 . 10.1093/brain/121.10.1819 . free . 9798740 .
  14. Teeple . Ryan C. . Caplan . Jason P. . Stern . Theodore A. . Visual Hallucinations: Differential Diagnosis and Treatment . The Primary Care Companion to the Journal of Clinical Psychiatry . 15 February 2009 . 11 . 1 . 26–32 . 10.4088/pcc.08r00673 . 19333408 . 2660156 .
  15. Perala . Jonna . Suvisaari . Jaana . Saarni . Samuli I. . Kuoppasalmi . Kimmo . Isometsa . Erkki . Pirkola . Sami . Partonen . Timo . Tuulio-Henriksson . Annamari . Hintikka . Jukka . Kieseppa . Tuula . Harkanen . Tommi . Koskinen . Seppo . Lonnqvist . Jouko . Lifetime Prevalence of Psychotic and Bipolar I Disorders in a General Population . Archives of General Psychiatry . January 2007 . 64 . 1 . 19–28 . 10.1001/archpsyc.64.1.19 . 17199051 . free .
  16. . Block . Michael N. . An overview of visual hallucinations: patients who experience hallucinations secondary to a host of underlying conditions often will look to you for guidance, reassurance and treatment . Review of Optometry . 15 March 2012 . 149 . 3 . 82–91 .
  17. Goodwin . Donald W. . Rosenthal . Randall . Clinical Significance of Hallucinations in Psychiatric Disorders: A study of 116 hallucinatory patients . Archives of General Psychiatry . January 1971 . 24 . 1 . 76–80 . 10.1001/archpsyc.1971.01750070078011 . 5538855 .
  18. Mott . Richard H . Small . Iver F . Anderson . John M . Comparative Study Of Hallucinations . Archives of General Psychiatry . June 1965 . 12 . 6 . 595–601 . 10.1001/archpsyc.1965.01720360067011 . 14286889 .
  19. . Ali . Shahid . Patel . Milapkumar . Avenido . Jaymie . Bailey . Rahn K. . Jabeen . Shagufta . Riley . Wayne J. . Hallucinations: common features and causes: awareness of manifestations, nonpsychiatric etiologies can help pinpoint a diagnosis . Current Psychiatry . November 2011 . 10 . 11 . 22–27 .

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