Repetitive behavior disorders in autism

Autism is associated with a wide range of repetitive behaviors. These behaviors, although diagnostic for the disorder, have been the subject of far less attention than social and communication deficits. An understanding of the phenomenology, including comorbidity, of various forms of abnormal repetition requires improved methodology, including use of item-independent instruments capable of discriminating categories of repetitive behaviors or movements. The motivation or function of these repetitive behaviors is uncertain, although a number of mechanisms have been advanced including escape, attention, arousal modulation, sensory reinforcement, and stress reduction. Relevant neurobiological studies point to alterations in basal ganglia function and potentially in medial temporal pole as key pathophysiological features of repetitive behavior disorders. In particular, striatal dopamine interactions with serotonin and opioid peptides appear to subserve, at least in part, expression of the behaviors. The efficacy of dopaminergic, serotonergic, and opiate drugs in diminishing repetitive behavior disorders and their effects in relevant animal models supports such a neurobiological basis. MRDD Research Reviews 1998;4:80–89. © 1998 Wiley-Liss, Inc.