Low salivary cortisol and persistent aggression in boys referred for disruptive behavior

Background: Persistent antisocial behavior in adulthood is often preceded by childhood-onset aggressive conduct disorder. Aggressive syndromes in both children and adults have previously been associated with abnormalities in peripheral responses to stress. One peripheral measure, salivary cortisol concentration, may reflect individual differences in the hypothalamic-pituitary-adrenal axis that underlie propensities for aggression, socialization, and adaptation to stress. Methods: The relationship between salivary cortisol levels and aggression was tested in 38 clinic-referred school-aged boys. Persistent aggression was measured by collecting disruptive behavior disorder symptoms in 4 annual clinical evaluations and peer nominations of aggression in the first 2 annual evaluations. Salivary cortisol levels were measured during years 2 and 4 of the study. Results: Low cortisol levels were associated with persistence and early onset of aggression, particularly when measures of cortisol concentrations were pooled. Boys with low cortisol concentrations at both time points exhibited triple the number of aggressive symptoms and were named as most aggressive by peers 3 times as often as boys who had higher cortisol concentrations at either sampling time, Conclusions: This suggests that low hypothalamic-pituitary-adrenal axis activity is a correlate of severe and persistent aggression in male children and adolescents. A restricted (low) range of cortisol variability may be more indicative of persistent aggression than a low concentration of cortisol at any single point in time.