An independent analysis of the copenhagen sample of the Danish adoption study of schizophrenia. I. The relationship between anxiety disorder and schizophrenia.

Familial factors have been shown to be important in the transmission of both anxiety disorder and schizophrenia. The familial relationship between these two disorders, however, has received little attention. This study examines the relationship between anxiety disorder and schizophrenia by a blind independent analysis of the interviews from the Danish Adoption Study of Schizophrenia using DSM-III criteria. The results show neither a genetic nor a familial-environmental link between the two disorders. These results are not consistent with the unitary hypothesis of mental illness. From a genetic and familial-environmental perspective, anxiety disorder and schizophrenia appear to be distinct, unrelated psychiatric illnesses.