Children with comorbid attention deficit hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD) exhibit signs of underfunctional hypothalamic- pituitary-adrenal (HPA) function, according to a new study.
S. H. Kariyawasam et al. measured salivary cortisol levels in 32 children with both ADHD and ODD, and 25 controls. Abnormal cortisol measurements may reflect dys- regulation of the HPA axis, which regulates cortisol levels.
The researchers found that salivary cortisol levels were significantly lower in the ADHD/ODD group than in the controls, but only in ADHD/ODD children not taking Ritalin-a drug that increases cortisol levels. These findings, they say, "support the possibility of a dysfunction of control of the hypothalamic-pituitary-adrenal axis in these behaviorally disturbed children," which could stem from under-arousal or other causes. They suggest that Ritalin may reduce the symptoms of many ADHD children by elevating cortisol levels.
Earlier studies (see Crime Times Vol. 6, No. 2, 2000, p. 4 and Vol. 7, No. 2, 2001, p. 2) (see related articles, Crime Times, 2000, Vol. 6, No. 2, Page 4 and Crime Times, 2001, Vol. 7, No. 2, Page 2) have detected low salivary cortisol levels in boys with early-onset and persistent aggression, and in girls with conduct disorder.
"Reduced salivary cortisol in children with comorbid attention deficit hyperactivity disorder and oppositional defiant disorder," S. H. Kariyawasam, F. Zaw, and S. L. Handley, Neuroendocrinology Letter, Vol. 23, No. 1, February 2002, 45-8. Address: S. H. Kariyawasam, Department of Pharmacology, University of Columbo Faculty of Medicine, Columbo 08, Sri Lanka, firstname.lastname@example.org.