Delusional disorders

A delusion is a fixed belief that is not amenable to change in light of conflicting evidence. As a pathology (delusional disorder), it is distinct from a belief based on false or incomplete information, confabulation, dogma, illusion, hallucination, or some other misleading effects of perception, as individuals with those beliefs are able to change or readjust their beliefs upon reviewing the evidence. However:

psychopathological condition (that is, when an individual believes that he has exceptional abilities, fame, wealth, or omnipotence)

mental disease

Erotomania, also known as '''de Clérambault's syndrome''', is an uncommon paranoid condition that is characterized by an individual's delusions of another person being infatuated with them. It is listed in the DSM-5 as a subtype of a delusional disorder. Commonly, the onset of erotomania is sudden, and the course is chronic.

psychiatric disorder (syndrome) in which a person holds a delusion that a family member has been replaced by an identical imposter

mental illness featuring beliefs with inadequate grounding

shared psychosis, a psychiatric syndrome in which symptoms of a delusional belief are transmitted from one individual to another

psychopathological symptom

psychopathological syndrome

Morgellons () is the informal name of a self-diagnosed, scientifically unsubstantiated skin condition in which individuals have sores that they believe contain fibrous material. Morgellons is not well understood, but the general medical consensus is that it is a form of delusional parasitosis, on the psychiatric spectrum. The sores are typically the result of compulsive scratching, and the fibers, when analysed, are consistently found to have originated from cotton and other textiles.

type of delusion in which the person believes that their lives are staged reality shows, or that they are being watched on cameras

mental disorder

delusion involving perception of persecution

Paraphrenia is a mental disorder characterized by an organized system of paranoid delusions with or without hallucinations (the positive symptoms of schizophrenia) and without deterioration of intellect or personality (its negative symptoms).

belief that certain gestures, environmental cues, innocuous events, comments and so forth are directed at oneself

Pregnancy not noticed until labor

idea that preoccupies an individual

medical condition

Somatoparaphrenia is a type of monothematic delusion where one denies ownership of a limb or an entire side of one's body. Even if provided with undeniable proof that the limb belongs to and is attached to their own body, the patient produces elaborate confabulations about whose limb it really is or how the limb ended up on their body. In some cases, delusions become so elaborate that a limb may be treated and cared for as if it were a separate being.

psychopathological syndrome

delusional belief

Intermetamorphosis is a delusional misidentification syndrome, related to agnosia. The main symptoms consist of patients believing that they can see others change into someone else in both external appearance and internal personality. The disorder is usually comorbid with neurological disorders or mental disorders. The disorder was first described in 1932 by Paul Courbon (1879–1958), a French psychiatrist. Intermetamorphosis is rare, although issues with diagnostics and comorbidity may lead to under-reporting.

Boanthropy is a psychological disorder in which a human believes themselves to be a bovine.

Belief that others can hear someone's thoughts

state of mind in which a person expresses hypotheses unrelated to reality on only one topic