Unsolved:Visual hallucinations in psychosis

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Short description: Hallucinations accompanied by delusions

Visual hallucinations in psychosis are hallucinations accompanied by delusions.[1]

Presentation

Visual hallucinations in psychoses are reported to have physical properties similar to real perceptions. 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.[2][3][4][5][6][7][8]

Simple vs. complex

Visual hallucinations may be simple, or non-formed visual hallucinations, or complex, or formed visual hallucinations.

Simple visual hallucinations without structure are known as phosphenes and those with geometric structure are known as photopsias.[9][10][11] These hallucinations are caused by irritation to the primary visual cortex (Brodmann's area 17).[12]

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.[13][14]

Content

The frequency of hallucinations varies widely from rare to frequent, as does duration (seconds to minutes). The content of hallucinations varies as well. 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]

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.[12][15]

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.[14][15]

Prevalence

[9] The DSM-V lists visual hallucinations as a primary diagnostic criterion for several psychotic disorders, including schizophrenia and schizoaffective disorder.[1][10][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.[2][17][11]

References

  1. ↑ 1.0 1.1 American Psychiatric Association (2013). The Diagnostic and Statistical Manual Revision V (DSM-V). 
  2. ↑ 2.0 2.1 Goodwin, Donald W.; Rosenthal, Randall (January 1971). "Clinical Significance of Hallucinations in Psychiatric Disorders: A study of 116 hallucinatory patients". Archives of General Psychiatry 24 (1): 76–80. doi:10.1001/archpsyc.1971.01750070078011. PMID 5538855. 
  3. ↑ Gauntlett-Gilbert, Jeremy; Kuipers, Elizabeth (March 2003). "Phenomenology of Visual Hallucinations in Psychiatric Conditions". The Journal of Nervous and Mental Disease 191 (3): 203–205. doi:10.1097/01.nmd.0000055084.01402.02. PMID 12637850. 
  4. ↑ 4.0 4.1 4.2 Dudley, Robert; Wood, Markku; Spencer, Helen; Brabban, Alison; Mosimann, Urs P.; Collerton, Daniel (May 2012). "Identifying Specific Interpretations and Use of Safety Behaviours in People with Distressing Visual Hallucinations: An Exploratory Study". Behavioural and Cognitive Psychotherapy 40 (3): 367–375. doi:10.1017/S1352465811000750. PMID 22321567. http://doc.rero.ch/record/297045/files/S1352465811000750.pdf. 
  5. ↑ 5.0 5.1 5.2 Bracha, H. Stefan; Wolkowitz, Owen M.; Lohr, James B.; Karson, Craig N.; Bigelow, Llewellyn B. (April 1989). "High prevalence of visual hallucinations in research subjects with chronic schizophrenia". American Journal of Psychiatry 146 (4): 526–528. doi:10.1176/ajp.146.4.526. PMID 2929755. 
  6. ↑ 6.0 6.1 Lowe, Gordon R. (December 1973). "The phenomenology of hallucinations as an aid to differential diagnosis". The British Journal of Psychiatry 123 (577): 621–633. doi:10.1192/bjp.123.6.621. PMID 4772302. 
  7. ↑ 7.0 7.1 7.2 Frieske, David A.; Wilson, William P. (December 1966). "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 54: 49–62. PMID 5951932. 
  8. ↑ Assad, Ghazi; Shapiro, Bruce (September 1986). "Hallucinations: theoretical and clinical overview". The American Journal of Psychiatry 143 (9): 1088–1097. doi:10.1176/ajp.143.9.1088. PMID 2875662. 
  9. ↑ 9.0 9.1 Block, Michael N. (March 2012). "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 149 (3): 82–90. 
  10. ↑ 10.0 10.1 Cummings, Jeffrey L.; Miller, Bruce L. (January 1987). "Visual hallucinations: Clinical Occurrence and Use in Differential Diagnosis". The Western Journal of Medicine 146 (1): 46–61. PMID 3825109. 
  11. ↑ 11.0 11.1 Ali, Shahid; Patel, Milapkumar; Avenido, Jaymie; Bailey, Rahn K.; Jabeen, Shagufta; Riley, Wayne J. (November 2011). "Hallucinations: Common features and causes". Current Psychiatry 10 (11): 22–29. 
  12. ↑ 12.0 12.1 Price, John; Whitlock, Frances A.; Hall, R.T. (1983). "The psychiatry of vertebro-basilar insufficiency with the report of a case". Psychopathology 16 (1): 26–44. doi:10.1159/000283948. PMID 6844659. 
  13. ↑ 13.0 13.1 Manford, Mark; Andermann, Frederick (October 1998). "Complex visual hallucinations. Clinical and neurobiological insights". Brain 121 (10): 1819–1840. doi:10.1093/brain/121.10.1819. PMID 9798740. 
  14. ↑ 14.0 14.1 Menon, G. Jayakrishna; Rahman, Imran; Menon, Sharmila J.; Dutton, Gordon N (January 2003). "Complex Visual Hallucinations in the Visually Impaired: The Charles Bonnet Syndrome". Survey of Ophthalmology 48 (1): 58–72. doi:10.1016/S0039-6257(02)00414-9. PMID 12559327. 
  15. ↑ 15.0 15.1 Teeple, Ryan C.; Caplan, Jason P.; Stern, Theodore A. (2009). "Visual Hallucinations: Differential Diagnosis and Treatment". Prim Care Companion J Clin Psychiatry 11 (1): 26–32. doi:10.4088/pcc.08r00673. PMID 19333408. 
  16. ↑ Perala, Jonna; Suvisaari, Jaana; Saarni, Samuli I.; Kuoppasalmi, Kimmo; Isometsa, Erkki; Pirkola, Sami; Partonen, Timo; Tuulio-Henriksson, Annamari et al. (January 2007). "Lifetime Prevalence of Psychotic and Bipolar I Disorders in a General Population". Archives of General Psychiatry 64 (1): 19–28. doi:10.1001/archpsyc.64.1.19. PMID 17199051. 
  17. ↑ Mott, Richard H; Small, Iver F; Anderson, John M (June 1965). "Comparative Study Of Hallucinations". Archives of General Psychiatry 12 (6): 595–601. doi:10.1001/archpsyc.1965.01720360067011. PMID 14286889. 



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