Cortisol awakening response in healthy children and children with ADHD: impact of comorbid disorders and psychosocial risk factors.

Attention-deficit/hyperactivity disorder (ADHD) is one of the most common child psychiatric disorders. Previous studies have reported a blunted cortisol response to challenging situations and a decreased cortisol awakening response (CAR) in children with ADHD. As ADHD often is comorbid with oppositional defiant disorder (ODD), conduct disorder (CD), or anxiety disorder (AnxD), and changes in hypothalamic-pituitary-adrenal (HPA) axis activity have also been reported for these disorders, the present study aimed to compare the CAR in children with ADHD with and without comorbid disorders. Data on the CAR were obtained in 128 children with ADHD (aged 6-13 years) and in 96 control children (aged 6-12 years). Children with ADHD+ODD showed an attenuated CAR (area under the curve, AUC) compared to children with ADHD without ODD/CD and control children. Findings point towards either disinhibition or pervasive underarousal in children with ADHD+ODD, and seem to be specific for children with ADHD+ODD, as the attenuated CAR-AUC was not observed in children with ADHD without comorbid disorders or children with ADHD+CD or ADHD+AnxD. In addition, current adverse parenting conditions, family conflicts, and acute life events were associated with mean increase in CAR, emphasizing the role of psychosocial risk factors in mediating HPA axis activity in children with ADHD.