Diagnostic Criteria

A. Delusions are the predominant clinical feature.

B. There is no clouding of consciousness, as in Delirium; there is no significant loss of intellectual abilities, as in Dementia; there are no prominent hallucinations, as in Organic Hallucinosis.

C. There is evidence, from the history, physical examination, or laboratory tests, of a specific organic factor that is judged to be etiologically related to the disturbance.

Differential Diagnosis

Nonorganic psychotic disorders

Nonorganic psychotic disorders such as Schizophrenia or Paranoid Disorders must be distinguished from Organic Delusional Syndrome. Differentiation rests primarily on evidence, gathered from the history, physical examination, or laboratory tests, of a specific organic factor judged to be responsible for the development of the delusions. The appearance of delusions de novo in an individual over the age of 30 years without a known history of Schizophrenia or Paranoid Disorder should always alert the diagnostician to the possibility of an Organic Delusional Syndrome. On the other hand, the fact that an individual has a prior history of nonorganic psychosis does not mean that one should neglect consideration of an Organic Delusional Syndrome, especially if there is concern about a possible organic factor (for example, the ingestion of an hallucinogen).

Organic Hallucinosis and Organic Affective Syndrome

In Organic Hallucinosis, hallucinations are the predominant feature. Delusions, if present, are related to the hallucinations. In Organic Affective Syndrome, symptoms resembling those of the Affective Disorders predominate. Delusions and hallucinations, if present, have a content related to the mood disturbance.


See Substance-Induced Psychotic Disorder

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