title: Genetic methods and preventive psychiatry.
abstract: 1. The meaning of the consistently high estimates of heritability of psychiatric disorders such as affective disorders and schizophrenia is that a small proportion of families accounts for a very large proportion of the population diagnostic variance. 2. This implies that the classic community mental health services model of a randomly distributed risk in a geographically defined catchment area population is inappropriate, and that efficient case finding and follow-up would result from tracing illness within pedigrees of known cases. 3. Application to clinical practice of family study methods developed in genetic research enables efficient identification of unrecognized and untreated cases, and early provision of care (secondary prevention). The use of family study methods will also uncover milder and variant ("spectrum") forms of illness in relatives of known patients, which then become accessible to treatment. 4. A family study of affective illness at the United States National Institute of Mental Health, demonstrated how additional ill persons including previously untreated cases could be identified. Starting with 86 Bipolar probands, we interviewed all available first degree relatives, and saw second degree relatives if there was indicated psychopathology by history. 5. Of the 405 living first degree relatives of 86 Bipolar I patients, the study found 1.2% had lifetime diagnosis of untreated Bipolar illness, 2.7% had untreated Unipolar illness, 4% had less severe personality disorders and 2% suffered from behavioral disorders such as drug abuse or alcoholism.
mesh_terms: D001714:Bipolar Disorder / Q000235:genetics / Q000517:prevention & control; D006801:Humans; D001523:Mental Disorders / Q000235:genetics* / Q000517:prevention & control; D012107:Research Design