If a child loves to bite, first of all, we need to exclude organic causes, such as some diseases of the brain (tumor, infection, poisoning, etc.), and possibly pervasive developmental disorder (autism), mental retardation (mental retardation). If the child’s previous performance is normal, then the child may be suffering from mood disorders, such as anxiety, depression, etc., by biting people to vent bad emotions, then through family memories or careful observation, you can find that in addition to love biting, the child should also have other aspects of performance, such as upset, emotional instability, easy to lose temper, timid and fearful crying, poor sleep, etc.. You can go to the psycho-psychiatric department of a regular hospital for diagnosis and treatment.