Generally speaking, the core symptoms are hyperactivity , inattention , and impulsivity . In boys, hyperactivity is evident, for example, in their inability to sit still, difficulty remaining seated, and running and jumping at inappropriate times. In girls, hyperactivity may manifest more subtly, such as inner restlessness, anxiety, or heightened sensitivity. Regarding impulsivity , some symptoms may include constantly interrupting, difficulty waiting their turn, answering prematurely, or engaging in thoughtless and risky behaviors. Finally, inattention is commonly characterized by losing objects and materials, disorganization in tasks, appearing not to listen when spoken to, being constantly distracted, or difficulty concentrating on unmotivating tasks.