Early development of stereotyped and self-injurious behaviors

Literature on early development of typical and abnormal stereotyped and self-injurious behaviors was reviewed. Such behaviors are part of normal development, but abnormalities can be detected from birth to Age 3. Many of these behaviors reach a maximum level around Age 2 and then decline. The behaviors may be retained in some children, however, and around the time the child reaches school age, the behaviors may increase. Increase and decline of typical behaviors are delayed in children with developmental delays. The relationship between early and later behaviors has not been studied Although many abnormal behaviors may emerge from typical behaviors in infancy, some behaviors definitely do not. Possibly, the 2nd year is a sensitive period for emergence of abnormal stereotyped and self-injurious behaviors and treatments might be most effective then. Tests of efficacy of treatments to prevent these behaviors are rare.