Stereotypic movement disorder is a medical condition in which a person repeatedly makes movements that have no purpose, including activities such as body rocking, head banging, or nail biting. Movements must continue for a minimum of four weeks to indicate stereotypic movement disorder. In addition, the movements are potentially harmful to afflicted person and might interfere with his or her normal activities.
A person with stereotypic movement disorder might bite, hit, or pick at himself or herself. In addition, he or she might engage in eye gouging, nose picking, or thumb sucking, as well as flapping, shaking, or waving his or her hands, making stereotyped sounds, or playing with hair. He or she might display a variety of stereotypic movements, or just one. When he or she becomes bored, frustrated, or stressed, the occurrence of his or her stereotypic movements might increase in frequency.
The actual cause of stereotypic movement disorder is unknown, although the disorder is caused by an array of medical conditions including brain disease and psychiatric disorders. Also, drug use can lead to stereotypic movements as well. In some people, the underlying cause of the disorder might remain a mystery. Theories about stereotypic movement disorder vary, with some attributing the condition to arise through behavioral means, while others suggest genetic or neurological origins.
Stereotypic movement disorder occurs more often in boys. In addition, although the disorder is found in people of all ages, it most commonly occurs in adolescence. Infants and toddlers exhibit certain stereotypic movements, such as thumb sucking, but these movements tend to disappear by the time the child becomes three or four years old. Even though these movements are associated with the disorder, they do not indicate that a child has the condition. As age plays a factor in the confirmation of the disorder, it is taken into consideration during diagnosis.
Depending on the cause of the disorder, stereotypic movements might disappear over time, or they might be permanent. For example, a person who displays these movements as a result of drugs will find that they usually go away, but a person whose movements are caused by a head injury might find that his or her condition is permanent. After adolescence, stereotypic movements might decrease and then disappear altogether, although they can come back periodically if triggered by stress or other factors. Treatment itself includes behavior modification, psychotherapy, and, in some cases, medications as well. To decrease the bodily harm that a person with the disorder might inflict on himself or herself, treatment might also involve making changes in the environment.