Correlations between Personality Structure and Adrenocortical Excretion Patterns in MZ Twins

Abstract

Twenty-one pairs of healthy MZ twins, all males 18-21 years of age, have been studied for possible correlations between individual personality characteristics and relatively constant patterns of pituitary-adrenocortical functioning. Subjects were studied by means of psychiatric interviews, Rorschach and other psychological tests, and 35 24-hour urine collections for 17-hydroxycorticosteroid (17OHCS) and 17-ketosteroid (17KS) determinations.Our previous observations have been reported, both on these healthy male volunteers (Fox et al, 1961 and 1965) and on various clinical syndromes (Rizzo et al, 1954; Fox et al, 1958; Gifford and Gunderson, 1970). Our cumulative clinical impressions suggested that high levels of 17OHCS excretion are found in individuals with an intense need for close personal relationships, or with an equally intense need to defend themselves against emotional involvement, by active forms of avoidance and denial. Low 17OHCS levels were found in individuals who were more effectively defended against emotional intimacy by well-organized neurotic defenses, with some isolation, constriction of affect or less conscious awareness of conflict.In studying twins, however, an unusual pattern of high 17KS and low 17OHCS compelled us to pay more attention to the significance of 17KS levels. High 17KS excretion patterns were found in energetic, ambitious individuals, with strong aggressive drives or equally strong defenses against them. Individuals with low 17KS levels were overcon trolled, with limited drive-endowment and widespread inhibitions of impulse and action.