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 Pitts2,3 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 schizophrenics4,5 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 al7 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
Ebaugh IA, Freiman M, Woolf RB, Sherman AI, Winokur G. Chromosome Studies in Patients With Affective Disorder (Manic-Depressive Illness). Arch Gen Psychiatry. 1968;19(6):751-752. doi:10.1001/archpsyc.1968.01740120111015