Amish Study, III: the impact of cultural factors on diagnosis of bipolar illness.

In the Amish Study of affective disorders, 79% of the 28 active bipolar I patients, diagnosed according to Research DIagnostic Criteria, previously had received hospital record diagnoses of schizophrenia. Both cultural and clinical factors hindered correct diagnosis, and cultural influences particularly complicated the interpretation of the manic symptoms of grandiosity and excessive involvement in activities. Other factors central to misdiagnosis were form of thought (flight of ideas), content of thought (grandiose and religious delusions), paranoid features, and the failure to recognize the presence of a manic syndrome.