Young children who are typically developing frequently make simple stereotypical movements (such as rocking; in the US and UK, this ranges from 5% to 18%). Complex stereotypic movements are substantially less frequent (happening in 3%–4% of cases). In samples from high-income nations, between 4% and 16% of people with intellectual developmental disorder (intellectual impairment) engage in stereotypy and self-harm. People with severe intellectual developmental disorders are more at risk. 10% to 15% of people with intellectual developmental disorders who dwell in residential facilities may also self-injure and have stereotypic movement disorder. In children with severe intellectual developmental disorders, repetitive and constrained behaviors and interests may be risk factors for the onset of self-harm, violence, and destructive conduct.