Delusional disorder as a partial psychosis.

In his textbook from 1838, Esquirol made the first comprehensive psychopathological description of paranoia, which he labeled partial psychosis. This was a condition with encapsulated, well organized, and persistent delusions. These are defended with a great deal of emotions and sharp argument. The individual appears quite convincing, especially because he or she otherwise behaves rationally. The intellectual capacity is used to achieve defined goals according to the delusional content. This condition is difficult to uncover because of dissimulation and adaptation. The frequency in the population is unknown, but the condition is rare in psychiatric treatment facilities, and usually only when the persons become litigious or criminal. In Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, the condition is covered by the concept of delusional disorder, but that concept also comprises benign acute/subacute conditions as well as cases that turn out to have the diagnosis changed to schizophrenia.