Hallucinations: Common features and causes

Awareness of manifestations, nonpsychiatric etiologies can help pinpoint a diagnosis

ot all patients who experience have a psychotic disorder. Many physical and Npsychiatric disorders can manifest with hal- lucinations, and some patients have >1 disorder that could cause different types of hallucinations. To avoid providing unnecessary or ineffective treatments—and to ensure that patients receive proper care for nonpsy- chiatric conditions—it is important to accurately diag- nose the disorder causing a patient’s hallucinations. In this article we describe common features and psy- chiatric and nonpsychiatric causes of auditory, visual, olfactory, gustatory, tactile, and somatic hallucinations. Awareness of typical presentations of hallucinations associated with specific disorders can help narrow the

© IMAGEZOO/CORBIS diagnosis and provide appropriate treatment. Shahid Ali, MD Assistant Professor, Clinical Milapkumar Patel, MD Auditory hallucinations Research Associate Also known as paracusia, auditory hallucinations are Jaymie Avenido, MD of sounds without identifiable external Research/Forensic Psychiatry Associate stimuli. This type of has various causes Rahn K. Bailey, MD, FAPA 1 Associate Professor (Table 1). A frequent symptom of , audi- Shagufta Jabeen, MD tory hallucinations can cause substantial distress and Assistant Professor, Clinical Psychiatry functional disability.2 Approximately 60% to 90% of pa- Wayne J. Riley, MD, MPH, MBA, MACP tients with schizophrenia and up to 80% of those with Professor of Family Medicine affective psychoses experience auditory hallucinations.1 • • • • Auditory hallucinations in usually are Department of Psychiatry and Behavioral Sciences formed and complex.3 A common manifestation is Meharry Medical College Nashville, TN ≥1 voices. A patient might experience 2 voic- es talking about him in the third person. The voices Current Psychiatry 22 November 2011 may be perceived as coming from inside or outside the patient’s head. Some might hear their Table 1 own thoughts spoken aloud. According to DSM-IV-TR, “hearing voices” is sufficient Common causes of auditory to diagnose schizophrenia if the hallucina- hallucinations tions consist of a voice keeping up a run- Peripheral lesions ning commentary on the person’s behavior Middle ear disease or ≥2 voices conversing with each other.4 Inner ear disease Auditory hallucinations also are seen in Auditory nerve disease mood disorders but tend to be milder than CNS disorders their psychosis-induced counterparts. Simple (unformed) auditory halluci- nations—referred to as —can be Pontine lesions caused by disease of the middle ear (oto- Stroke sclerosis) or inner ear. These unformed hal- Arteriovenous malformations lucinations consist of buzzing or tones of Syncope varying pitch and timbre.1 Toxic metabolic disturbances Partial may cause auditory Clinical Point hallucinations. Perceptions of music have Auditory perceptions 5 been associated with partial seizures. of music have been Curie and colleagues found that 17% of 514 Schizophrenia associated with patients with had auditory hallucinations as a component Psychotic partial seizures of their seizures.6 These hallucinations identity disorder typically are brief, stereotyped sensory Posttraumatic stress disorder impressions and, if formed, may be trivial Source: Reference 1 sentences, previously heard phrases, or commands. Alcoholic hallucinosis is a hallucinatory caused by withdrawal. may consist of formed images (eg, people) These hallucinations usually are vocal and or unformed images (eg, flashes of light).12 typically consist of accusatory, threaten- Visual hallucinations occur in numerous ing, and/or critical voices directed at the ophthalmologic, neurologic, medical, and patient.1 Patients with alcohol hallucino- psychiatric disorders (Table 2, page 24).13 sis also may experience musical auditory DSM-IV-TR lists visual hallucinations hallucinations.7,8 as a primary diagnostic criterion for sev- CNS neoplasms can produce auditory eral psychotic disorders, including schizo- hallucinations in 3% to 10% of patients.9 phrenia and ,4 and Hemorrhages and arteriovenous malfor- they occur in 16% to 72% of patients with mations in the pontine and these conditions.14,15 Patients with major lower midbrain have been associated with depressive disorder or acute onset of auditory hallucinations. The also may experience visual hallucinations. sounds typically are unformed mechanical Visual hallucinations in those with schizo- or seashell-like noises or music.10 phrenia tend to involve vivid scenes with Patients with rarely report family members, religious figures, and/or auditory hallucinations. When they occur, animals.16 they typically consist of perceived unilat- Delirium is a transient, reversible cause eral tinnitus, phonophobia, or hearing loss. of cerebral dysfunction that often presents with hallucinations. Several studies have shown that visual hallucinations are the Visual hallucinations most common type among patients with Visual hallucinations manifest as visual delirium. Webster and Holroyd found vi- sensory perceptions in the absence of ex- sual hallucinations in 27% of 227 delirium Current Psychiatry ternal stimuli.11 These false perceptions patients.17 Vol. 10, No. 11 23 continued Table 2 These simple visual hallucinations are most common; more complex hallucina- Common causes of visual tions are seen more frequently in hallucinations coma and familial hemiplegic migraine.

Neurologic disorders Approximately 5% of patients with epilepsy have occipital seizures, which al- Migraine most always have visual manifestations. Epilepsy Hallucinations Epileptic visual hallucinations often are Hemispheric lesions simple, brief, stereotyped, and fragmen- Optic nerve disorders tary. They usually consist of small, bright- Brain stem lesions () ly colored spots or shapes that flash.22 Complex visual hallucinations in epilepsy are similar to hypnagogic hallucinations Ophthalmologic diseases but are rare. Intracranial electroencepha- Glaucoma lography recordings have shown that Retinal disease pathological excitation of visual cortical Clinical Point Enucleation areas may be responsible for complex vi- Up to one-half Cataract formation sual hallucinations in epilepsy.19 Choroidal disorder Dementia with Lewy bodies (DLB) is of patients with 23 Macular abnormalities associated with visual hallucinations. Parkinson’s disease Visual hallucinations occur in >20% of pa- Toxic and metabolic conditions may experience tients with DLB.24 Patients with DLB may Toxic-metabolic visual hallucinations see complex scenarios of people and items Drug and alcohol withdrawal that are not present. Visual hallucinations Hallucinogens have an 83% positive predictive value for Schizophrenia distinguishing DLB from dementia of the 25 Affective disorders Alzheimer’s type. There is a strong cor- Conversion disorders relation between Lewy bodies located in the amygdala and parahippocampus and well-formed visual hallucinations.26 Visual hallucinations are common in Hypnosis Parkinson’s disease and may occur in Intense emotional experiences up to one-half of patients.27 Patients with Source: Reference 13 Parkinson’s disease may experience hallu- cinations similar to those observed in DLB, which can range from seeing a person or animal to more complex, formed, and mo- typically is accom- bile people, animals, or objects. panied by visual hallucinations. Visions of small animals and crawling insects are common.18 Hallucinations due to drug in- Olfactory hallucinations toxication or withdrawal generally vary Also known as , olfactory hal- in duration from brief to continuous; such lucinations involve smelling that ONLINE 19 ONLY experiences often contribute to agitation. are not derived from any physical stimu- Migraines are a well-recognized cause lus. They can occur with several psychi- Discuss this article at of visual hallucinations. Up to 31% of those atric conditions, including schizophrenia, www.facebook.com/ with migraines experience an , and depression, bipolar disorder, eating dis- CurrentPsychiatry nearly 99% of those with aura have visual orders, and substance abuse.28 Olfactory symptoms.20,21 The classic visual aura starts hallucinations caused by epileptic activity as an irregular colored crescent of light are rare. They constitute approximately with multi-colored edges in the center of 0.9% of all auras and typically are described the that gradually progresses as unpleasant. Tumors that affect the me- Current Psychiatry 24 November 2011 toward the periphery, lasting <60 minutes. dial temporal lobe and mesial temporal sclerosis are associated with olfactory hal- lucinations.29 Olfactory hallucinations also Related Resource have been reported in patients with multi- • Teeple RC, Caplan JP, Stern TA. Visual hallucinations: differ- ential diagnosis and treatment. Prim Care Companion J Clin infarct dementia, Alzheimer’s disease, and Psychiatry. 2009;11(1):26-32. alcoholic psychosyndromes. In patients Disclosures with schizophrenia, the smell may be per- Drs. Ali, Patel, Avenido, Bailey, and Jabeen report no financial ceived as coming from an external source, relationship with any company whose products are men- tioned in this article or with manufacturers of competing whereas patients with depression may products. 30 perceive the source as internal. Patients Dr. Riley is on the board of directors for Vertex Pharmaceuticals. who perceive that they are the source of Acknowledgment an offensive —a condition known as The authors would like to thank Marwah Shahid, Research olfactory reference syndrome—may wash Associate, Vanderbilt University, Nashville, TN. excessively, overuse deodorants and per- fumes, or become socially withdrawn.30

Tactile hallucinations have been associ- Gustatory hallucinations ated with obsessive-compulsive disorder Clinical Point Patients with gustatory hallucinations may (OCD).37 Fontenelle and colleagues suggest- Sinus diseases experience salivation, sensation of thirst, or ed that OCD and psychotic disorders may have been linked alterations. These hallucinations can share dysfunctional dopaminergic circuits.37 be observed when the sylvian fissure that to olfactory extends to the insula is stimulated electri- and gustatory cally.31 Similar to olfactory hallucinations, Somatic hallucinations hallucinations gustatory hallucinations are associated Patients who have somatic hallucinations with temporal lobe disease and parietal report perceptions of abnormal body sen- operculum lesions.31,32 Sinus diseases have sations or physical experiences. For exam- been associated with olfactory and gusta- ple, a patient may have of not having tory hallucinations.33 Brief gustatory hallu- a stomach while eating.35 cinations can be elicited with stimulation This type of hallucination has been asso- of the right rolandic operculum, parietal ciated with activation of postcentral gyrus, operculum, amygdala, , me- parietal operculum, insula, and inferior pa- dial temporal gyrus, and anterior part of rietal lobule on stereoelectroencephalogra- right temporal gyrus.34 phy.34 In a study of cerebral blood flow in 20 geriatric patients with , somatic type who were experiencing so- Tactile hallucinations matic hallucinations, positron emission test- These hallucinations may include percep- ing demonstrated increased perfusion tions of insects crawling over or under the in somatic regions, par- skin () or simulation of pressure ticularly the left postcentral gyrus and the on skin.35 They have been associated with right paracentral lobule.38 Other researchers substance abuse, toxicity, or withdrawal.28 have linked somatic hallucinations with ac- Tactile hallucinations are characteristic of tivation in the primary somatosensory and or amphetamine intoxication.35 posterior parietal cortex, areas that normal- Tactile hallucinations are a rare symp- ly mediate tactile .39 tom of schizophrenia. Heveling and col- leagues reported a case of a woman, age References 1. Cummings JL, Mega MS. Hallucinations. In: Cummings 68, with chronic schizophrenia who expe- JL, Mega MS, eds. and behavioral neuroscience. New York, NY: Oxford University Press; 2003: rienced touching and being touched by a 187-199. “shadow man” several times a day in ad- 2. Shergill SS, Murray RM, McGuire PK. Auditory hallucinations: a review of psychological treatments. dition to auditory and visual hallucina- Schizophr Res. 1998;32(3):137-150. 36 tions. Her symptoms disappeared after 3. Goodwin DW, Alderson P, Rosenthal R. Clinical significance 4 weeks of and mood stabi- of hallucinations in psychiatric disorders. A study of 116 hallucinatory patients. Arch Gen Psychiatry. 1971;24(1): Current Psychiatry lizer therapy. 76-80. Vol. 10, No. 11 25 continued on page 29 continued from page 25

4. Diagnostic and statistical manual of mental disorders, 23. Ballard CG, O’Brien JT, Swann AG, et al. The natural history 4th ed, text rev. Washington, DC: American Psychiatric of psychosis and depression in dementia with Lewy bodies Association; 2000. and Alzheimer’s disease: persistence and new cases over 1 5. Kasper BS, Kasper EM, Pauli E, et al. Phenomenology of year of follow-up. J Clin Psychiatry. 2001;62(1):46-49. hallucinations, , and as part of 24. Ala TA, Yang KH, Sung JH, et al. Hallucinations and signs semiology. Epilepsy Behav. 2010;18(1-2):13-23. of parkinsonism help distinguish patients with dementia 6. Currie S, Heathfield KW, Henson RA, et al. Clinical course and cortical Lewy bodies from patients with Alzheimer’s and prognosis of temporal lobe epilepsy. A survey of 666 disease at presentation: a clinicopathological study. J Neurol patients. Brain. 1971;94(1):173-190. Neurosurg Psychiatry. 1997;62(1):16-21. 7. Keshavan MS, David AS, Steingard S, et al. Musical 25. Tiraboschi P, Salmon DP, Hansen LA, et al. What best hallucinations: a review and synthesis. Cogn Behav Neurol. differentiates Lewy body from Alzheimer’s disease in early- 1992;5(3):211-223. stage dementia? Brain. 2006;129(Pt 3):729-735. 8. Duncan R, Mitchell JD, Critchley EMR. Hallucinations and 26. Harding AJ, Broe GA, Halliday GM. Visual hallucinations music. Behav Neurol. 1989;2(2):115-124. in Lewy body disease relate to Lewy bodies in the temporal lobe. Brain. 2002;125(Pt 2):391-403. 9. Tarachow S. The clinical value of hallucinations in localizing brain tumors. Am J Psychiatry. 1941;97:1434-1442. 27. Williams DR, Lees AJ. Visual hallucinations in the diagnosis of idiopathic Parkinson’s disease: a retrospective autopsy 10. Lanska DJ, Lanska MJ, Mendez MF. auditory study. Lancet Neurol. 2005;4(10):605-610. hallucinosis. Neurology. 1987;37(10):1685. 28. Lewandowski KE, DePaola J, Camsari GB, et al. Tactile, 11. Norton JW, Corbett JJ. Visual perceptual abnormalities: olfactory, and gustatory hallucinations in psychotic hallucinations and illusions. Semin Neurol. 2000;20(1): disorders: a descriptive study. Ann Acad Med Singapore. 111-121. 2009;38(5):383-385. 12. Kaplan HI, Sadock BJ, Grebb JA. Typical signs and 29. Acharya V, Acharya J, Lüders H. Olfactory epileptic auras. symptoms of psychiatric illness defined. In: Kaplan HI, Neurology. 1998;51(1):56-61. Sadock BJ, Grebb JA, eds. Kaplan and Sadock’s synopsis of psychiatry: behavioral sciences, clinical psychiatry. 30. Ropper AH, Samuels MA. Disorders of smell and taste. Clinical Point Baltimore, MD: Williams and Wilkins; 1994:300. In: Ropper AH, Samuels MA, eds. Adams and Victor’s principles of neurology. 9th ed. New York, NY: McGraw-Hill 13. Cummings JL, Miller BL. Visual hallucinations. Clinical Companies; 2009:216-224. Sensations of occurrence and use in differential diagnosis. West J Med. 1987;146(1):46-51. 31. Ropper AH, Samuels MA. Epilepsy and other seizure insects crawling on disorders. In: Ropper AH, Samuels MA, eds. Adams and 14. First MB, Tasman A. Schizophrenia and other psychoses. Victor’s principles of neurology. 9th ed. New York, NY: In: First MB, Tasman A, eds. Clinical guide to the diagnosis or under the skin McGraw-Hill Companies; 2009:304-338. and treatment of mental disorders. San Francisco, CA: John Wiley and Sons; 2009:245-278. 32. Capampangan DJ, Hoerth MT, Drazkowski JF, et al. are characteristic Olfactory and gustatory hallucinations presenting as partial 15. Mueser KT, Bellack AS, Brady EU. Hallucinations in status epilepticus because of glioblastoma multiforme. Ann of cocaine or schizophrenia. Acta Psychiatr Scand. 1990;82(1):26-29. Emerg Med. 2010;56(4):374-377. 16. Small IF, Small JG, Andersen JM. Clinical characteristics 33. Frasnelli J, Reden J, Landis BN, et al. Comment on “Olfactory amphetamine of hallucinations of schizophrenia. Dis Nerv Syst. 1966; hallucinations as a manifestation of hidden rhinosinusitis”. 27(5):349-353. J Clin Neurosci. 2010;17(4):543. intoxication 17. Webster R, Holroyd S. Prevalence of psychotic symptoms in 34. Elliott B, Joyce E, Shorvon S. Delusions, illusions and delirium. Psychosomatics. 2000;41(6):519-522. hallucinations in epilepsy: 1. Elementary phenomena. 18. Gastfriend DR, Renner JA, Hackett TP. Alcoholic patients: Epilepsy Res. 2009;85(2-3):162-171. acute and chronic. In: Stern TA, Fricchione G, Cassem 35. Nurcombe B, Ebert MH. The psychiatric interview. In: Ebert NH, et al, eds. Massachusetts General Hospital handbook MH, Nurcombe B, Loosen PT, et al, eds. Current diagnosis of general hospital psychiatry. 5th ed. Philadelphia, PA: and treatment: psychiatry. 2nd ed. New York, NY: McGraw- Mosby; 2004:203-216. Hill Companies; 2008:95-114. 19. Manford M, Andermann F. Complex visual hallucinations. 36. Heveling T, Emrich HM, Dietrich DE. Treatment of a rare Clinical and neurobiological insights. Brain. 1998;121(Pt 10): psychopathological phenomenon: tactile hallucinations and 1819-1840. the delusional other. Eur Psychiatry. 2004;19(6):387-388. 20. Goadsby PJ, Lipton RB, Ferrari MD. Migraine—current 37. Fontenelle LF, Lopes AP, Borges MC, et al. Auditory, visual, understanding and treatment. N Engl J Med. 2002;346(4): tactile, olfactory, and bodily hallucinations in patients with 257-270. obsessive-compulsive disorder. CNS Spectr. 2008;13(2):125-130. 21. Russell MB, Olesen J. A nosographic analysis of the 38. Nemoto K, Mizukami K, Hori T, et al. Hyperperfusion migraine aura in a general population. Brain. 1996;119(Pt 2): in primary somatosensory region related to somatic 355-361. hallucination in the elderly. Psychiatry Clin Neurosci. 2010; 22. Panayiotopoulos CP. Elementary visual hallucinations, 64(4):421-425. blindness, and headache in idiopathic occipital epilepsy: 39. Shergill SS, Cameron LA, Brammer MJ, et al. Modality specific differentiation from migraine. J Neurol Neurosurg neural correlates of auditory and somatic hallucinations. Psychiatry. 1999;66(4):536-540. J Neurol Neurosurg Psychiatry. 2001;71(5):688-690.

Bottom Line Auditory, visual, olfactory, gustatory, tactile, and somatic hallucinations can be caused by a wide range of physical and psychiatric conditions. Awareness of common presentations of hallucinations associated with specific disorders can Current Psychiatry help narrow the diagnosis and lead to more efficacious treatment. Vol. 10, No. 11 29