Autism is a lifelong, non-progressive developmental disability that is the result of as yet unspecified impairments to normal brain development from potentially multiple and variably overlapping causes. Autism is a syndrome, known by a characteristic set of impairments in social interaction, in communication and in the capacity for imaginitive and symbolic thinking resulting in stilted and stereo-typed interests, behavior and activities.
The severity of impairment in each of these domains varies along a continuum and the particular manifestations of impairments may be very diverse. Thus, those with autism may appear quite different from each other with respect to sensory sensitivities, the regulation of attention, behavioral and emotional self-control, activity level, attachment to others, resistance to change and cognitive functioning. Because of the diversity of presentation and functioning shown by those with autism, individuals now may be typically described as having Autism Spectrum Disorder.