What is "stereotypic movement disorder"?

Stereotypic movement disorder: The symptoms include the following. It is more common in boys than girls and the cause is unknown. It must. Cause distress or risk of harm. Naltrexone may be of some benefit. Biting self hand shaking or waving head banging hitting own body mouthing of objects nail biting rocking. www.ncbi.nlm.nih.gov/pubmedhealth/pmh0002515 stereotypic movement disorder.