The following can indicate a delusion: # An individual expresses an idea or belief with unusual persistence or force, even when evidence suggests the contrary. # That idea appears to have an undue influence on the person's life, and the way of life is often altered to an inexplicable extent. # Despite their profound conviction, there is often a quality of secretiveness or suspicion when the person is questioned about it. # The individual tends to be humorless and oversensitive, especially about the belief. # There is a quality of centrality: no matter how unlikely it is that these strange things are happening to the person, he or she accepts them relatively unquestioningly. # An attempt to contradict the belief is likely to arouse an inappropriately strong emotional reaction, often with irritability and hostility. They will not accept any other opinions. # The belief is, at the least, unlikely, and out of keeping with the individual's social, cultural, and religious background. # The person is emotionally over-invested in the idea and it overwhelms other elements of his or her psyche. # The delusion, if acted out, often leads to behaviors which are abnormal, and out of character, although perhaps understandable in light of the<unk>  beliefs. # Other people who know the individual observe that the belief and behavior are uncharacteristic and alien. Additional features of<unk>  include the following: # It is a primary disorder. # It is a stable disorder characterized by the presence of delusions to which the patient clings with extraordinary tenacity. # The illness is chronic and frequently lifelong. # The delusions are logically constructed and internally consistent. # The delusions do not interfere with general logical reasoning (although within the<unk>  system the logic is perverted) and there is usually no general disturbance of behavior. If disturbed behavior does occur, it is directly related to the<unk>  beliefs. # The individual experiences a heightened sense of self-reference. Events which, to others, are nonsignificant are of enormous significance to him or her, and the atmosphere surrounding the delusions is highly charged. However this should not be confused with gaslighting, where a person denies the truth, and causes the victim to think that they are being<unk> .
Delusional disorder
Paranoid personality disorder
Externalizing disorder
Substance-induced psychosis
Internalizing disorder
Bipolar disorder
Dissociative disorder
Schizophrenia