The etiology and pathogenesis of ADHD is unclear, but there is ample evidence that ADHD is a neurodevelopmental disorder, which is a syndrome caused singly or synergistically by a variety of biological factors (including genetic factors, environmental factors, brain development abnormalities, etc.), psychological factors, and social factors.

ADHD is mainly characterized by distraction which does not match with age, reduced attention span, excessive activity and emotional impulses regardless of occasion, accompanied by cognitive impairment and learning difficulties, and intelligence is normal or near normal. The core symptoms of ADHD include attention deficit, hyperactivity and impulsivity.

There are two main methods of ADHD management: (1) pharmacological treatment; (2) non- pharmacological treatment: including behavioral therapy, parent training, etc.
For more information see your Doctor or Healthcare Professional.
  

郑毅, 刘靖主编. 中国注意缺陷多动障碍防治指南(第二版). 中华医学电子音像出版社. 2015.