An adoption study of depressive disorders and substance abuse.

Registered psychiatric illness was studied in the biologic and adoptive parents of 115 adoptees with affective disorders or histories of substance abuse. The parents of these patients were compared with those of 115 control subjects who were pairwise matched for demographic and social variables and who had no psychiatric illness. Psychiatric patients had a fivefold excess of adoptive fathers who had psychiatric illness compared with fathers of their matched controls. This was due to an excess of affective disorders in adoptive fathers regardless of the sex or diagnosis of the adopted child. Biologic mothers of female patients had a threefold increase in psychiatric illness compared with mothers of their matched controls and a fourfold increase compared with mothers of male adoptees. However there was no significant concordance between specific diagnoses in biologic parents and their adopted-away children. Subdivision of depressive patients according to psychotic-nonpsychotic and reactive-nonreactive dichotomies did not yield subgroups with distinct family histories.