Testing for physical illness in psychiatric patients.

The presence of causative, exacerbating, or coexisting medical illness is often missed by both psychiatric and nonpsychiatric physicians. Reasons for these misdiagnoses are examined, and it is suggested that the evaluation of psychiatric patients should include a detailed physical examination, thorough medical and psychiatric history, including the use of informants in addition to the patient, and laboratory testing. The willingness to consider nonobvious causes of psychiatric symptoms can help to avoid premature diagnostic closure and inappropriate treatment.