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What is Psychosis?

Updated: Jul 6, 2023

Like many mental disorders, the definition of psychosis has changed throughout different editions of the American Psychiatric Association’s (APA) Diagnostic and Statistical Manual of Mental Disorders (DSM). In early editions of the DSM, “psychosis was defined broadly as “gross impairment in reality testing” or “loss of ego boundaries” that interferes with the capacity to meet the ordinary demands of life” [1]. Since this definition is so broad, there were issues with differentiating mental disorders with symptoms of psychosis and mental disorders without symptoms of psychosis. Many mental disorders, even nonpsychotic ones, can affect individuals’ abilities to meet the ordinary demands of life like the definition emphasizes.


“In their current conceptualization of psychosis, both the APA and the World Health Organization [WHO] define psychosis narrowly by requiring the presence of hallucinations (without insight into their pathologic nature), delusions, or both” [1]. So, this is definitely a more specific definition of psychosis, but what exactly are classified as hallucinations and delusions? “Delusions (ie, fixed false beliefs) [...] are evidence of impaired reality testing: delusional beliefs are ones maintained steadfastly even in the face of evidence contradicting them incontrovertibly. Similarly, hallucinations (ie, perceptions occurring in the absence of corresponding external or somatic stimuli) are evidence of impaired reality when the individual experiencing them is unable to recognize the hallucinatory nature of such experiences” [1]. Both of these are extremely important for diagnosing a psychotic disorder since “impaired reality testing remains central conceptually to psychosis” [1]. To clear up some language, “hallucinations without insight” means that the person suffering from the hallucinations isn’t able to recognize that they are not real. “Examples of hallucinations with preserved insight include the visual hallucinations of migraine aura, sleep transition-related hypnagogic (while falling asleep) and hypnopompic (while waking) hallucinations, and the hallucinated hearing of one’s name being called that many psychiatrically and neurologically healthy individuals experience occasionally” [1].


There are two types of delusions that are commonly experienced by those with psychotic disorders. “Ordinary delusions derive from misinterpretation of everyday experiences and, as such, are understandable but not accepted by other members of the person’s culture or subculture” [1]. An example of an ordinary delusion might be someone being convinced that a friend or family member is stealing money from their  bank account even though their bank records show that nothing has changed. “Bizarre delusions involve phenomena that are physically impossible or that most people in that person’s culture would regard as entirely implausible” [1]. An example of a bizarre delusion might be “the belief that a stranger removed one’s internal organs and replaced them with another person’s organs without leaving any wounds or scars” [1].


Understanding what is classified as a hallucination and a delusion is important when addressing symptoms of psychosis. Since these are both the main qualifiers for diagnosing an individual with psychosis, it’s important to make sure the differentiation between similar symptoms is clear to avoid a misdiagnosis.



1. Arciniegas D. B. (2015). Psychosis. Continuum (Minneapolis, Minn.), 21(3 Behavioral Neurology and Neuropsychiatry), 715–736.




Author: Lauryn Agron

Editor: Kayjah Taylor

Health Scientist: Naiya Upadhyay


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