Chromosome Studies in Patients With Affective Disorder (Manic-Depressive Illness)

CONSIDERABLE evidence points to a genetically determined predisposition to affective disorder. In Kallman's study, the concordance rate for monozygotic twins was 100%; for dizygotic twins, 25.5%; for full siblings, 22.7%; for half siblings, 16.7%; and for parents of probands, 23.4%. 1 Winokur and Pitts 2,3 have presented data showing that siblings and parents of affective disorder probands have a higher rate of affective disorder themselves than the siblings and parents of control subjects. Chromosome studies have been reported on schizophrenics 4,5 and other groups of psychiatric patients, 6 but not on a group of manic-depressive patients. Materials and Methods All of the patients with affective disorder were adults and met the criteria of Cassidy et al 7 for the diagnosis of manic-depressive illness. During the first phase of this project, 13 patients with affective disorder were studied. Of these, ten patients had a positive family history