High levels of cortisol among adolescent offspring of parents with bipolar disorder: a pilot study.

The hypothalamic-pituitary-adrenal (HPA) axis is compromised at several levels in major depressive and bipolar disorder (BD). However, it is not known whether HPA abnormalities predate the onset of these disorders. We conducted a pilot study comparing salivary cortisol levels of 10 adolescent offspring of parents with BD and 10 offspring of parents with no mental disorder (NMD). For two days, samples were collected at awakening and during the day in the adolescents' natural environment. The offspring of parents with BD had higher mean cortisol levels in the mornings and afternoons than the offspring of parents with NMD. When controlling for age, group differences in cortisol persisted in the afternoon, but not morning samples. None of the adolescents met diagnostic criteria for anxiety, affective, attention-deficit, or conduct disorders. Although preliminary, the results suggest that there is an early abnormality in the HPA system of the offspring of parents with BD.