Depressive Disorders and HLA

To the Editor: In the article by Weitkamp et al. on “Depressive Disorders and HLA” (November 26 issue)¹ siblings of an affected proband were considered unaffected (i.e., without an affective disorder) if they did not manifest a depressive illness by the age of 30. Although the authors explain that they do not expect all such siblings to remain unaffected, this arbitrary age criterion limits the conclusions that can be drawn from the study. Although a positive family history is associated with a younger age at the onset of affective disorders, probably less than half the patients in whom an affective.