THE GENETIC-BASIS OF PERSONALITY AT DIFFERENT AGES - A CROSS-SECTIONAL TWIN STUDY

The hypothesis that the stability of personality in adults is owing to genetic factors was examined by fitting genetic path models in a samp le of young adult twins (122 monozygotic and 121 dizygotic pairs aged 18-25 yr) and a sample of older adult twins (145 monozygotic and 136 d izygotic pairs aged 30-65 yr). The significance of genetic factors in personality, as measured by the Dimensional Assessment of Personality Pathology (DAPP) at these two ages was tested. It was found that model s that specified no genetic factors did not fit the data on 15 of 18 D APP dimensions in the older adult twins, in contrast to only seven dim ensions in the younger adult twins. These results suggest that role of genetic factors is more significant in later as opposed to early adul thood and may account for the greater stability of personality observe d during the course of adult life. Copyright (C) 1996 Elsevier Science Ltd.