ADHD is a common abnormal behavior problem of children, which is mainly manifested as difficulty in concentration, short attention, excessive activity and emotional impulse, thus affecting academic performance. It is difficult to get along with people at home and at school, which makes it difficult for parents and teachers in their daily lives.

Etiology of ADHD:

1. Genetic factors play an important role in the etiology of ADHD, with an average heritability of 0.76 and family aggregation;

2. Neurophysiological factors, the abnormal rate of EEG in ADHD children is high, mainly due to the increase of slow wave activity;

3. Mild brain injury caused by various reasons during pregnancy, perinatal period and after birth may be the cause of ADHD in some children;

4. Neurobiochemical factors may be related to the decrease of dopamine and epinephrine renewal rate and the low function of dopamine and norepinephrine;

5. Neuroanatomical factors of decrease of corpus callosum and caudate nucleus in 5.ADHD children:

6. Psychosocial factors, bad social environment, family environment, improper educational methods, poor economy, and broken parents' feelings will all increase the risk of ADHD;

7. Other factors may be related to the deficiency of zinc and iron and the increase of blood lead. In addition, food additives may also increase the risk of ADHD in children.