Current Psychiatry Reports

, Volume 8, Issue 3, pp 191–204 | Cite as

Delusions in the nonclinical population

  • Daniel Freeman


Delusions have long been considered a hallmark of psychotic disorders such as schizophrenia. However, delusions may only be most visibly present in psychotic conditions and could also occur in nonclinical groups. The aim of this review is to establish whether delusions, as traditionally considered and assessed in psychiatric conditions, are also present in individuals without a psychiatric or neurologic condition. Clear evidence is found that the rate of delusional beliefs in the general population is higher than the rate of psychotic disorders and that delusions occur in individuals without psychosis. The frequency of delusional beliefs in nonclinical populations varies according to the content of the delusion studied and the characteristics of the sample population. Approximately 1% to 3% of the nonclinical population have delusions of a level of severity comparable to clinical cases of psychosis. A further 5% to 6% of the nonclinical population have a delusion but not of such severity. Although less severe, these beliefs are associated with a range of social and emotional difficulties. A further 10% to 15% of the nonclinical population have fairly regular delusional ideation. There is convincing evidence that delusional ideation, delusions, and clinically severe delusions are related experiences. Information about clinical delusions can therefore be obtained by studying delusional ideation in nonclinical populations.


Psychotic Symptom Psychotic Disorder Paranoid Ideation Psychotic Experience Epidemiologic Catchment Area 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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References and Recommended Reading

  1. 1.
    Jablensky A: The epidemiological horizon. In Schizophrenia. Edited by Hirsch SR, Weinberger DR. Oxford: Blackwell Publishing; 2003:203–231.Google Scholar
  2. 2.
    Strauss JS: Hallucinations and delusions as points on continua function. Rating scale evidence. Arch Gen Psychiatry 1969, 21:581–586.PubMedGoogle Scholar
  3. 3.
    Chapman LJ, Chapman JP: Scales for rating psychotic and psychotic-like experiences as continua. Schizophr Bull 1980, 6:476–489.Google Scholar
  4. 4.
    Claridge G: Schizotypy: Implications for Illness and Health. Oxford: Oxford University Press; 1997.Google Scholar
  5. 5.
    Peters ER, Joseph SA, Garety PA: The measurement of delusional ideation in the normal population: introducing the PDI (Peters et al. Delusions Inventory). Schizophr Bull 1999, 25:553–576.PubMedGoogle Scholar
  6. 6.
    van Os J, Verdoux H: Diagnosis and classification of schizophrenia: categories versus dimensions, distributions versus disease. In The Epidemiology of Schizophrenia. Edited by Murray RM, Jones PB, Susser E, et al. Cambridge, UK: Cambridge University Press; 2003:364–410.Google Scholar
  7. 7.
    Johns LC: Hallucinations in the general population. Curr Psychiatry Rep 2005, 7:162–167.PubMedGoogle Scholar
  8. 8.
    Claridge G: Single indicators of risk for schizophrenia. Probably fact or likely myth? Schizophr Bull 1994, 20:151–168.PubMedGoogle Scholar
  9. 9.
    Oltmanns TF: Approaches to the definition and study of delusions. In Delusional Beliefs. Edited by Oltmanns TF, Maher BA. New York: Wiley; 1988:3–12.Google Scholar
  10. 10.
    Garety PA, Hemsley DR: Delusions: Investigations into the Psychology of Delusional Reasoning. Oxford: Oxford University Press; 1994.Google Scholar
  11. 11.
    Peralta V, Cuesta MJ: Factor structure and clinical validity of competing models of positive symptoms in schizophrenia. Biol Psychiatry 1998, 44:107–114.PubMedCrossRefGoogle Scholar
  12. 12.
    Freeman D, Garety PA, Bebbington PE, et al.: Psychological investigation of the structure of paranoia in a non-clinical population. Br J Psychiatry 2005, 186:427–435.PubMedCrossRefGoogle Scholar
  13. 13.
    Kendler KS, Gallagher TJ, Abelson JM, Kessler RC: Lifetime prevalence, demographic risk factors, and diagnostic validity of nonaffective psychosis as assessed in a US community sample. Arch Gen Psychiatry 1996, 53:1022–1031.PubMedGoogle Scholar
  14. 14.
    Reiger D, Myers JK, Kramer M, et al.: Historical context, major objectives and study design. In Epidemiologic Field Methods in Psychiatry. Edited by Eaton WW, Kessler LG. Orlando, FL: Academic Press; 1985.Google Scholar
  15. 15.
    Eaton WW, Romanoski A, Anthony JC, Nestadt G: Screening for psychosis in the general population with a self-report interview. J Nerv Ment Dis 1991, 179:689–693. This is one of the first studies to report in detail on delusions in a representative general population sample. A very thorough methodology is used.PubMedCrossRefGoogle Scholar
  16. 16.
    Robins LN, Helzer JE, Croughan J, Ratcliff KA: National Institute of of Mental Health Diagnostic Interview Schedule. Arch Gen Psychiatry 1981, 38:381–389.PubMedGoogle Scholar
  17. 17.
    van Os J, Hanssen M, Bijl RV, Ravelli A: Strauss (1969) revisited: a psychosis continuum in the general population. Schizophr Res 2000, 45:11–20. This landmark publication shows very convincingly that nonclinical individuals in the general population can experience delusions. There is a very helpful distinction between clinically severe and not clinically severe delusions. Associations with demographic risk factors are also examined.PubMedCrossRefGoogle Scholar
  18. 18.
    Robins LN, Wing J, Wittchen H, et al.: The Composite International Diagnostic Interview. Arch Gen Psychiatry 1988, 45:1069–1077.PubMedGoogle Scholar
  19. 19.
    Tien AY, Anthony JC: Epidemiological analysis of alcohol and drug use as risk factors for psychotic experiences. J Nerv Ment Dis 1990, 178:473–480.PubMedGoogle Scholar
  20. 20.
    Poulton R, Caspi A, Moffitt TE, et al.: Children’s selfreported psychotic symptoms and adult schizophreniform disorder. Arch Gen Psychiatry 2000, 57:1053–1058. This excellent and important study examines the development of psychotic symptoms prospectively in a birth cohort. Psychotic symptoms were assessed at ages 11 and 26 years; symptoms at age 11 predicted development of psychosis in adulthood. This is the first examination of links between childhood and adult symptoms.PubMedCrossRefGoogle Scholar
  21. 21.
    Robins LN, Cottler L, Bucholz K, Compton W: Diagnostic Interview Schedule for DSM-IV. St. Louis: Washington University; 1995.Google Scholar
  22. 22.
    Johns LC, Cannon M, Singleton N, et al.: The prevalence and correlates of self-reported psychotic symptoms in the British population. Br J Psychiatry 2004, 185:298–305.PubMedCrossRefGoogle Scholar
  23. 23.
    Bebbington PE, Nayani T: The Psychosis Screening Questionnaire. Int J Methods Psychiatr Res 1995, 5:11–19.Google Scholar
  24. 24.
    Scott J, Chant D, Andrews G, McGrath J: Psychotic-like experiences in the general community. Psychol Med 2006, 36:231–238.PubMedCrossRefGoogle Scholar
  25. 25.
    World Health Organization: Composite Diagnostic Interview—Version 1.1. Geneva: World Health Organization; 1993.Google Scholar
  26. 26.
    Tien AY, Eaton WW: Psychopathologic precursors and sociodemographic risk factors for the schizophrenia syndrome. Arch Gen Psychiatry 1992, 49:37–46.PubMedGoogle Scholar
  27. 27.
    Christenson R, Blazer D: Epidemiology of persecutory ideation in an elderly population in the community. Am J Psychiatry 1984, 141:1088–1091.PubMedGoogle Scholar
  28. 28.
    Kincannon JC: Predictions of the standard MMPI scale scores from 71 items: the mini-mult. J Consult Clin Psychol 1968, 32:319–325.PubMedCrossRefGoogle Scholar
  29. 29.
    Forsell Y, Henderson AS: Epidemiology of paranoid symptoms in an elderly population. Br J Psychiatry 1998, 172:429–432.PubMedGoogle Scholar
  30. 30.
    Åsberg M, Montgomery SA, Perris C, et al.: A comprehensive psychopathological rating scale. Acta Psychiatr Scand Suppl 1978, 271:5–27.PubMedGoogle Scholar
  31. 31.
    Lyketsos CG, Steinberg M, Tschanz JT, et al.: Mental and behavioral disturbances in dementia: findings from the Cache County Study on Memory in Aging. Am J Psychiatry 2000, 157:708–714.PubMedCrossRefGoogle Scholar
  32. 32.
    Cummings JL, Mega M, Gray K, et al.: The Neuropsychiatric Inventory: comprehensive assessment of psychopathology in dementia. Neurology 1994, 44:2308–2314.PubMedGoogle Scholar
  33. 33.
    Östling S, Skoog I: Psychotic symptoms and paranoid ideation in a nondemented population-based sample of the very old. Arch Gen Psychiatry 2002, 59:53–59. The authors carry out a very thorough assessment of delusions in a birth cohort of people who have reached age 85 years. They show that in an older adult group (without dementia), a significant minority experience delusions and delusional ideation.PubMedCrossRefGoogle Scholar
  34. 34.
    Cohen CI, Magai C, Yaffee R, Walcott-Brown L: Racial differences in paranoid ideation and psychoses in an older urban population. Am J Psychiatry 2004, 161:864–871.PubMedCrossRefGoogle Scholar
  35. 35.
    Derogatis LR, Lipman RS, Covi L: SCL-90: an outpatient psychiatric rating scale—preliminary report. Psychopharmacol Bull 1973, 9:13–28.PubMedGoogle Scholar
  36. 36.
    Olfson M, Lewis-Fernández R, Feder A, et al.: Psychotic symptoms in an urban general medicine practice. Am J Psychiatry 2002, 159:1412–1419. This is a very good study that highlights that individuals attending an urban general medicine practice experience delusions fairly frequently. It also shows that these experiences are often accompanied by emotional distress and difficulties with social functioning.PubMedCrossRefGoogle Scholar
  37. 37.
    Sheehan DV, Lecrubier Y, Sheehan KH, et al.: The Mini-International Neuropsychiatric Interview. J Clin Psychiatry 1998, 59(Suppl 20):22–33.PubMedGoogle Scholar
  38. 38.
    Verdoux H, Maurice-Tison S, Gay B, et al.: A survey of delusional ideation in primary-care patients. Psychol Med 1998, 28:127–134.PubMedCrossRefGoogle Scholar
  39. 39.
    Wing JK, Cooper JE, Sartorius N: Measurement and Classification of Psychiatric Symptoms. Cambridge, UK: Cambridge University Press; 1974.Google Scholar
  40. 40.
    Peters E, Joseph S, Day S, Garety P: Measuring delusional ideation: the 21-item Peters et al. Delusions Inventory (PDI). Schizophr Bull 2004, 30:1005–1022.PubMedGoogle Scholar
  41. 41.
    Lundberg P, Cantor-Graae E, Kabakyenga J, et al.: Prevalence of delusional ideation in a district in southwestern Uganda. Schizophr Res 2004, 71:27–34.PubMedCrossRefGoogle Scholar
  42. 42.
    Claridge G, McCreery C, Mason O, et al.: The factor structure of "schizotypal" traits: a large replication study. Br J Clin Psychol 1996, 35:103–115.PubMedGoogle Scholar
  43. 43.
    Krabbendam L, Myin-Germeys I, Hanssen M, et al.: Hallucinatory experiences and onset of psychotic disorder: evidence that the risk is mediated by delusion formation. Acta Psychiatr Scand 2004, 110:264–272.PubMedCrossRefGoogle Scholar
  44. 44.
    Garety PA, Freeman D, Jolley S, et al.: Reasoning, emotions and delusional conviction in psychosis. J Abnorm Psychol 2005, 114:373–384.PubMedCrossRefGoogle Scholar
  45. 45.
    Van Dael F, Versmissen D, Janssen I, et al.: Data gathering: biased in psychosis? Schizophr Bull 2006, 32:341–351.PubMedCrossRefGoogle Scholar
  46. 46.
    Freeman D, Garety PA, Bebbington P, et al.: The psychology of persecutory ideation II: a virtual reality experimental study. J Nerv Ment Dis 2005, 193:309–315.PubMedCrossRefGoogle Scholar
  47. 47.
    Myin-Germeys I, Krabbendam L, van Os J: Continuity of psychotic symptoms in the community. Curr Opin Psychiatry 2003, 16:443–449.CrossRefGoogle Scholar
  48. 48.
    Chapman LJ, Chapman JP, Kwapil TR, et al.: Putatively psychosis-prone subjects 10 years later. J Abnorm Psychol 1994, 103:171–183.PubMedCrossRefGoogle Scholar
  49. 49.
    Chadwick PDJ, Birchwood MJ: The omnipotence of voices: a cognitive approach to hallucinations. Br J Psychiatry 1994, 164:190–201.PubMedCrossRefGoogle Scholar
  50. 50.
    Freeman D, Garety PA, Kuipers E: Persecutory delusions: developing the understanding of belief maintenance and emotional distress. Psychol Med 2001, 31:1293–1306.PubMedCrossRefGoogle Scholar
  51. 51.
    Freeman D, Garety PA: Worry, worry processes and dimensions of delusions: an exploratory investigation of a role for anxiety processes in the maintenance of delusional distress. Behav Cogn Psychother 1999, 27:47–62.Google Scholar
  52. 52.
    van Os J, Krabbendam L, Myin-Germeys I, Delespaul P: The schizophrenia envirome. Curr Opin Psychiatry 2005, 18:141–145.PubMedCrossRefGoogle Scholar
  53. 53.
    Jaspers K: General Psychopathology, edn 7. Translated by Hoenig J, Hamilton MW. Manchester: Manchester University Press; 1963.Google Scholar
  54. 54.
    Fowler D, Garety PA, Kuipers L: Cognitive Behaviour Therapy for Psychosis: Theory and Practice. Chichester: Wiley; 1995.Google Scholar
  55. 55.
    Freeman D, Freeman J, Garety PA: Overcoming Paranoid and Suspicious Thoughts. London: Robinson Constable; 2006. This is the first self-help book for paranoid thinking. It is written for the general public. It describes in detail the experience and causes of suspicious and paranoid thoughts and outlines cognitive-behavioral techniques to overcome these fears. It can also be helpful for clinicians working with clients.Google Scholar

Copyright information

© Current Science Inc. 2006

Authors and Affiliations

  1. 1.Department of PsychologyInstitute of Psychiatry, Kings College LondonLondonUK

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