Delusional misidentification syndromes and dementia: a border zone between neurology and psychiatry.

The delusional misidentification syndromes (DMSs) are psychopathologic phenomena in which a patient consistently misidentifies persons, places, objects, or events. Although often described in relation to psychotic states including schzofrenia, it is, nevertheless, widely considered that these syndromes have an anatomical basis because of their frequent association with organic brain disease; studies have pointed to the presence of identifiable lesions, especially in the right frontal lobe and adjacent regions, in a considerable proportion of patients. The purpose of this article is to examine the phenomenon in people with dementia.

Sociopathic behavior and dementia.

The maintenance of appropriate social behavior is a very complex process with many contributing factors. Social and moral judgments rely on the proper functioning of neural circuits concerned with complex cognitive and emotional processes. Damage to these systems may lead to distinct social behavior abnormalities.

Dangerous passion: Othello syndrome and dementia.

Jealousy is a complex emotion that most people have experienced at some time in life; pathological jealousy refers primarily to an irrational state. Othello syndrome is a psychotic disorder characterized by delusion of infidelity or jealousy; it often occurs in the context of medical, psychiatric or neurological disorders. At least 30% of cases in the literature show a neurological basis for their delusion of infidelity, although its biological basis is not fully understood.

A romantic delusion: de Clerambault's syndrome in dementia.

Erotromania (also known as de Clerambault's syndrome) is a rare disorder in which an individual has a delusional belief that a person of a socially higher standing falls in love with her/him. It has rarely been described in older people, but many cases have been reported in conjunction with psychiatric and neurological disorders. The purpose of this paper was to examine the phenomenon of erotomania in people with dementia.