Assessment and Differential Diagnosis - Mental Disorders Due to a General Medical Condition

Assessment and Differential Diagnosis

As noted earlier, psychotic disorder due to a general medical condition is a disorder which by definition occurs in a clear sen-sorium, without any associated decrement in intellectual abili-ties: both delirium and dementia are commonly accompanied by hallucinations and delusions, but these conditions are clearly distinguished from psychotic disorder due to a general medical condition by the presence of confusion or significant intellectual deficits.

In most cases, a thorough history and physical examina-tion will disclose evidence of the underlying cause of the psy-chosis in question. In those cases, however, where the patient’s symptomatology is atypical for one of the primary causes of psychosis (e.g., schizophrenia), yet the history and physical ex-amination fail to disclose clear evidence for another cause, a “laboratory screen,” as listed in Table 33.2, may be appropriate. Clearly, one does not order all these tests at once, but begins with

those most likely, given the overall clinical picture, to be most informative.