A review of genetic factors in depressive affects

This paper contains a review of genetic factors in depressive affects. A large number of research findings have been reported for this purpose, the most important of these being the twin study. Monozygotic and dizygotic twins have been differentiated. It has been found that monozygotic twins have a higher concordance rate for affective illness than do dizygotic twins. Moreover, bipolar and unipolar illnesses were found in the relatives of unipolar patients only. Thus affective illness in the first degree of relatives of bipolar patients was more than 30%. Genetic transmission was also found in linkage relationship. Chromosomal studies have also been reported. Phenotypic variations have also been found to be responsible for affective illness. In conclusion, a better clinical, biochemical, and therapeutic investigation has been suggested for better understanding of genetic factors in affective illness.