There are no consistent findings on the etiology of tic disorders, and current research on the etiology of tic disorders is focused on genetic, neuroanatomical, neurobiochemical, and perinatal risk factors. Since tic disorders can be familially aggregated and tic disorders are common in children’s families, it has been suggested that the disorder may be related to genetic factors. Dopaminergic, 5-hydroxytryptaminergic, noradrenergic, cholinergic, γ-aminobutyric acid (GABA), and opioid system central neurotransmitter dysfunction may be associated with the development of tic disorder. Group A streptococcal infection, smoking during pregnancy, low birth weight, and stress have been suggested as risk factors for the development of tic disorders. Additional studies have shown that children born with birth injuries, asphyxia, and other adverse factors are more likely to develop this disorder. The development and severity of tics are also associated with the child’s current physical health status, stress, certain medications and food factors. Some studies suggest that immune dysfunction may also contribute to the onset or exacerbation of the disease, and some children have blinking, nasal aspiration, and facial muscle twitching due to recurrent upper respiratory infections or certain medications and food factors. Psychosocial factors such as family discord, parental divorce, death of a loved one, and excessive study load may also aggravate the symptoms; certain drugs such as central nervous system stimulants, antipsychotics, and stimulant foods may also trigger or aggravate the twitching symptoms, for example, some children with mild tic disorder with attention deficit hyperactivity disorder may develop tic-obscene syndrome after taking stimulants.