The genetics of schizophrenia: a review.

The evidence suggesting that genetic factors are involved in the etiology of schizophrenia is reviewed. Despite methodological and other difficulties, independent lines of research--family, twin, and adoption studies--point in a common direction: Persons genetically at risk for schizophrenia are more likely to become affected than those who are not. Current attempts to understand the mode of inheritance of the gene or genes involved have become increasingly sophisticated and, consequently, less accessible (and possibly useful) to clinicians and nongeneticist researchers. Guidelines are provided for the provision of genetic counseling to affected persons and their relatives. Such counseling is frequently enmeshed with multiple psychosocial (rather than strictly medical) issues and should be provided by professionals with appropriate training and experience in psychotherapy.