Hereditary-environmental differentiation of general neurotic, obsessive, and impulsive hysterical personality traits.

The inheritance of General Neurotic, Obsessive, and Impulsive Hysterical personality traits has been studied in a sampling of 260 female and male adult same-sexed twins. At least one of the twins in each pair had been treated for neurotic or borderline disorders. The results showed that the General neurotic and the obsessive personality factor had a significantly but moderately high hereditary component. The same was also true for more than half of the 17 separate personality scales. No personality scales emerged as highly hereditary. Therefore, each item was analyzed separately, and items classified as either distinctly hereditary or environmental were placed in each of these two groups. The items of the two groups were separately factor-analyzed, and three hereditary and three environmental main factors emerged. The hereditary factors seemed to represent a basic core in the three personality factors of the total questionnaire, whereas the environmental factors could be explained as derivatives of early representation of the basic hereditary core, influenced by familial and cultural patterns.