Carriers of congenital adrenal hyperplasia due to 21-hydroxylase (21-OH) deficiency demonstrate increased secretion of cortisol precursors after ACTH stimulation, suggestive of impaired cortisol production and compensatory increases in hypothalamic CRH secretion. Because both cortisol and CRH have behavioral effects, and hypothalamic CRH hypersecretion has been associated with chronic states of anxiety and depression, we performed endocrine and psychologic studies in consecutively admitted parents of patients with classic congenital adrenal hyperplasia due to 21-OH deficiency and parents of children with other chronic endocrine disorders. The number of excluded carriers because of pathologic reasons was higher than that of controls (P = 0.05). Carriers of 21-OH deficiency had a lower mean 24-h urinary free cortisol excretion (26.4 +/- 3.4 vs. 42.7 +/- 6.4 microg/d, P = 0.03) and higher peak ACTH (75.7 +/- 8.1 vs. 54.2 +/- 5.9 pg/ml, P = 0.04) and 17-hydroxyprogesterone (224.2 +/- 28.1 vs. 107.1 +/- 12.5 ng/dl, P < 0.001) concentrations post CRH stimulation than control subjects. Cortisol and androstenedione responses were similar in the two groups. Psychometric assessment performed by administering the State-Anxiety Inventory, Beck Depression Inventory, Profile of Mood States, Symptom Checklist-90R, and Temperament and Character Inventory revealed no differences between the two subject groups. Interestingly, a stepwise multiple linear regression model analysis in each population sample revealed that in carriers of 21-OH deficiency but not in the control subjects, a lower mean 24-h urinary free cortisol excretion and a higher ACTH response to ovine CRH stimulation predicted predisposition to obsessive-compulsive behavior, novelty seeking, reward dependence, and harm avoidance. We conclude that carriers of 21-OH deficiency appear to have mild hypocortisolism and compensatory changes of CRH secretion secondary to lower cortisol concentrations. These changes might predict mild predisposition of these subjects to physical and psychologic pathology, suggesting that larger studies are necessary.