Mental illness in the biological and adoptive relatives of schizophrenic adoptees: findings relevant to genetic and environmental factors in etiology

Previous studies by the author and his collaborators, Rosenthal, Wender, Schulsinger, and Jacobsen, of the biological and adoptive relatives of schizophrenic adoptees are reviewed in conjunction with more recent studies by Spitzer and Endicott and by Kendler, Gruenberg, and Strauss, who independently made operational diagnoses using the Research Diagnostic Criteria or DSM-III specifications, both of which showed good agreement with the authors' global diagnoses based on the descriptions in DSM-II. Both the DSM-III diagnoses and the authors' global diagnoses found a highly significant concentration of chronic, latent, and uncertain schizophrenia or schizotypal personality disorder in the biological relatives of adoptees who developed chronic schizophrenia. A response is made to recent criticisms published in this journal by Lidz and Blatt and by Abrams and Taylor.