“All families encounter stressors,” says Dr. Francisco X. Castellanos, a professor in the Department of Child and Adolescent Psychiatry and director of the Center for Neurodevelopmental Disorders at NYU Langone Medical Center...Add a family member with attention deficity hyperactivity disorder into the mix, and existing stress can be magnified. Castellanos says that an ADHD child, who usually exhibits intense behaviors to begin with, “may become even more hyperactive or impulsive in response to the stressors.”