Problem: A 10-year-old boy is evaluated for difficulty in school, hyperactivity, and poor impulse control. His parents report these behaviors are present at home and school. Which of the following criteria must also be met for an ADHD diagnosis? Need Assignment Help? A. Symptoms must have been present for at least 3 months. B. Symptoms must cause significant impairment in at least one setting. C. Symptoms must be observed before the age of 12. D. Symptoms must be resistant to behavioral therapy.