ADHD, also known as attention deficit hyperactivity disorder (ADHD), can begin around age 3. These children have normal or near-normal intelligence, but have deficits in learning, behavior and emotion. The presence or absence of ADHD in 3-year-old children can generally be determined based on clinical manifestations and ancillary tests. (1) excessive activity: the child is extraordinarily active, often with hands and feet, unable to sit still, talking too much, etc.; (2) difficulty in concentration: such as not being able to listen quietly, unable to concentrate on things, unable to pay attention to details, carelessness, losing things, etc.; (3) impulsive behavior: the child has poor self-control, irritability, crying, impulsivity, etc. The above symptoms are the core symptoms of ADHD and usually have diagnostic value. (1) Neurophysiological tests: including EEG and attention variable tests, which can directly detect the overall physiological function of the nervous system; (2) Behavioral tests: the abnormal behavior of the child can be detected through talks with the child, parents and teachers, and can also be directly detected and evaluated through behavioral scales; (3) Psychological tests: including intelligence tests, attention tests and other psychological tests, which can assess whether the child has ADHD and its severity. (3) Psychological tests: including intelligence tests, attention tests and other psychological tests, can assess the presence and severity of ADHD. (2) Treatment of ADHD in children The treatment of ADHD in children is based on comprehensive treatment, mainly including medication and behavioral treatment, as follows: 1) medication: under the guidance of a doctor, such as the choice of concentration, Ritalin and other medication; 2) behavioral treatment: including self-management, time management, school and family behavior control, etc., can also be carried out in professional medical institutions behavior training to improve the child’s symptoms. Symptoms.