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Classification and external resources
Specialty Lua error in Module:Wikidata at line 446: attempt to index field 'wikibase' (a nil value).
ICD-10 F20.0, F22.0, F22.8, F60.0
ICD-9-CM 295.3, 297.1, 297.2
Patient UK Paranoia
MeSH D010259
[[[d:Lua error in Module:Wikidata at line 863: attempt to index field 'wikibase' (a nil value).|edit on Wikidata]]]

Paranoia is a thought process believed to be heavily influenced by anxiety or fear, often to the point of irrationality and delusion.[1] Paranoid thinking typically includes persecutory, or beliefs of conspiracy concerning a perceived threat towards oneself (e.g. "Everyone is out to get me"). Paranoia is distinct from phobias, which also involve irrational fear, but usually no blame. Making false accusations and the general distrust of others also frequently accompany paranoia. For example, an incident most people would view as an accident or coincidence, a paranoid person might believe it was intentional.


The word paranoia comes from the Greek παράνοια (paranoia), "madness",[2] and that from παρά (para), "beside, by"[3] and νόος (noos), "mind".[4] The term was used to describe a mental illness in which a delusional belief is the sole or most prominent feature. In this definition, the belief does not have to be persecutory to be classified as paranoid, so any number of delusional beliefs can be classified as paranoia.[citation needed] For example, a person who has the sole delusional belief that he is an important religious figure would be classified by Kraepelin as having 'pure paranoia'.

According to Michael Phelan, Padraig Wright, and Julian Stern (2000),[5] paranoia and paraphrenia are debated entities that were detached from dementia praecox by Kraepelin, who explained paranoia as a continuous systematized delusion arising much later in life with no presence of either hallucinations or a deteriorating course, paraphrenia as an identical syndrome to paranoia but with hallucinations. Even at the present time, a delusion need not be suspicious or fearful to be classified as paranoid. A person might be diagnosed as a paranoid schizophrenic without delusions of persecution, simply because their delusions refer mainly to themselves.

Use in modern psychiatry

In the DSM-IV-TR, paranoia is diagnosed in the form of:[6]

According to clinical psychologist P. J. McKenna, "As a noun, paranoia denotes a disorder which has been argued in and out of existence, and whose clinical features, course, boundaries, and virtually every other aspect of which is controversial. Employed as an adjective, paranoid has become attached to a diverse set of presentations, from paranoid schizophrenia, through paranoid depression, to paranoid personality—not to mention a motley collection of paranoid 'psychoses', 'reactions', and 'states'—and this is to restrict discussion to functional disorders. Even when abbreviated down to the prefix para-, the term crops up causing trouble as the contentious but stubbornly persistent concept of paraphrenia."[9]


A popular symptom of paranoia is the attribution bias. These individuals typically have a biased perception of the world often exhibiting more hostile beliefs.[10] A paranoid person may view someone else's accidental behavior as though it is with intent or threatening.

An investigation of a non-clinical paranoid population found that feeling powerless and depressed, isolating oneself, and relinquishing activities are characteristics that could be associated with those exhibiting more frequent paranoia.[11] Some scientists have created different subtypes for the various symptoms of paranoia including erotic, persecutory, litigious, and exalted.[12]

Due to the suspicious and troublesome personality traits of paranoia, it is unlikely that someone with paranoia will thrive in interpersonal relationships. Most commonly paranoid individuals tend to be of a single status.[13] According to some research there is a hierarchy for paranoia. The least common types of paranoia at the very top of the hierarchy would be those involving more serious threats. Social anxiety is at the bottom of this hierarchy as the most frequently exhibited level of paranoia.[14]


Social and environmental

Social circumstances appear to be highly influential on paranoid beliefs. Based on data collected by means of a mental health survey distributed to residents of Juarez, Mexico and El Paso, Texas, Paranoid beliefs seem to be associated with feelings of powerlessness and victimization, enhanced by social situations. Potential causes of these effects included a sense of believing in external control, and mistrust which can be strengthened by lower socioeconomic status. Those living in a lower socioeconomic status may feel less in control of their own lives. In addition, this study explains that females have the tendency to believe in external control at a higher rate than males, potentially making females more susceptible to mistrust and the effects of socioeconomic status on paranoia.[15]

Emanuel Messinger reports that surveys have revealed that those exhibiting paranoia can evolve from parental relationships and dis-trustworthy environments. These environments could include being very disciplinary, stringent, and unstable. It was even noted that, "indulging and pampering (thereby impressing the child that he is something special and warrants special privileges)," can be contributing backgrounds.[16] Experiences likely to enhance or manifest the symptoms of paranoia include increased rates of disappointment, stress, and a hopeless state of mind.[17]

Discrimination has also been reported as a potential predictor of paranoid delusions. Such reports that paranoia seemed to appear more in older patients that had experienced higher levels of discrimination throughout their lives. In addition to this it has been noted that immigrants are quite susceptible to forms of psychosis. This could be due to the aforementioned effects of discriminatory events and humiliation.[18]


A paranoid reaction may be caused from a decline in brain circulation as a result of high blood pressure or hardening of the arterial walls.[16]

Based on data obtained by the Dutch NEMISIS project in 2005, there was an association between impaired hearing and the onset of symptoms of psychosis, which was based on a five-year follow up. Some older studies have actually declared that a state of paranoia can be produced in patients that were under a hypnotic state of deafness. This idea however generated much skepticism during its time.[19]

Theories and mechanisms

Abnormal reasoning

Many researchers[who?] like to believe that individuals with paranoia have some sort of cognitive deficit or impairment in reasoning ability. Studies have shown that there may not be a direct relationship between the impairments and psychotic delusions, but they rather impact other areas of an individual's life, such as social circumstances which can be important factors for delusions. Other research has shown that cognitive abilities may be altered when threats are involved.[20] This appears to be a common theme among those exhibiting psychotic delusions. An investigation involving one-hundred delusional patients did indeed reveal that these individuals may have a tendency to jump to conclusions rather than look for other potential information.[21]

Anomalous perceptual experiences

A very prominent example of this theory is the Capgras delusion or syndrome named after the psychiatrist Joseph Capgras.[22] This involves an individual perceiving that a certain important person within their life has been taken over by an impersonator. Ellis and Young (1990) report that the Capgras delusion may be a result of an impaired ability of recognition such as brain damage.[19] Those suffering from the Capgras syndrome tend to have more suspicious personalities and have unusual visualizations about the world and surrounding environments.[23]

Hyper-acute attention is said to be more common in those with paranoia by being able to attend to unfavorable emotions at a higher level. It is also likely that because paranoid personalities focus on threatening events and believe that most intentions are against them, they will be more inclined to recognize these behaviors more frequently.[20]

Motivational factors

The attribution model has been well talked about regarding paranoid or delusional individuals. The idea is that they like to assign issues to external events. Motivation behind this characteristic may involve the need for that person to develop a better self-image and maintain self-confidence. There have been debates about whether or not paranoid individuals are more likely to have a low or high self-perception, and results have been generated for both of these hypotheses.[24] Researchers have made a distinction between positive self-esteem and negative self-esteem revealing that paranoid delusional individuals have more of a negative self-evaluation.[25]

Violence and paranoia

It has generally been agreed upon that individuals with paranoid delusions will have the tendency to take action based on their beliefs.[26] More research is needed on the particular types of actions that are pursued based on paranoid delusions. Some researchers have made attempts to distinguish the different variations of actions brought on as a result of delusions. Wessely et al. (1993) did just this by studying individuals with delusions of which more than half had reportedly taken action or behaved as a result of these delusions. However, the overall actions were not of a violent nature in most of the informants. The authors note that other studies such as one by Taylor (1985), have shown that violent behaviors were more common in certain types of paranoid individuals, mainly those with a history of being offensive such as prisoners.[27]

Other researchers have found associations between childhood abusive behaviors and the appearance of violent behaviors in psychotic individuals. This could be a result of their inability to cope with aggression as well as other people, especially when constantly attending to potential threats in their environment.[28] The attention to threat itself has been proposed as one of the major contributors of violent actions in paranoid people, although there has been much deliberation about this as well.[29] Other studies have shown that there may only be certain types of delusions that promote any violent behaviors, persecutory delusions seem to be one of these.[30]

Having resentful emotions towards others and the inability to be able to understand what other people are feeling seem to have an association with violence in paranoid individuals. This was based on a study of paranoid schizophrenic's (one of the common mental disorders that exhibit paranoid symptoms) theory of mind capabilities in relation to empathy. The results of this study revealed specifically that although the violent patients were more successful at the higher level theory of mind tasks, they were not as good at being able to interpret others feelings.[31]

See also


  1. World English Dictionary (Collins English Dictionary - Complete & Unabridged 10th Edition, 2009, William Collins Sons & Co. Ltd.) 3. informal sense: intense fear or suspicion, esp when unfounded
  2. παράνοια, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on perseus Digital Library
  3. παρά, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on perseus Digital Library
  4. νόος, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on perseus Digital Library
  5. Phelan, Wright, and Stern (2000)
  6. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders
  7. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders p.690
  8. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders p.325
  9. McKenna (1997), p.238
  10. Bentall and Taylor (2006), p. 289
  11. Freeman et al. (2005)
  12. Deutsch and Fishman p. 1414-1415
  13. Deutch and Fishman (1963), p.1416
  14. Freeman et al. (2005), p.433
  15. Mirowski and Ross (1983)
  16. 16.0 16.1 Deutsch and Fishman (1963), p. 1408
  17. Deutsch and Fishman (1963), p. 1412
  18. Bentall and Taylor (2006), p. 280
  19. 19.0 19.1 Bentall and Taylor (2006), p.281
  20. 20.0 20.1 Bentall and Taylor (2006)
  21. Freeman et al. (2004), p. 674
  22. Capgras and Reboul-Lachaux (1923)
  23. Ellis and Young (1990), p.241
  24. Bentall and Taylor (2006), p. 284-286
  25. Barrowclough et al. (2003)
  26. Bental and Taylor (2006), p. 286
  27. Wessely et al. (1993)
  28. Bentall and Taylor(2006), p. 287
  29. Bentall and Taylor (2006), p. 287-288
  30. Bjorkly (2002)
  31. Abu-Akel and Abushua’leh (2004)


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Further reading