Autism is a developmental disorder that is characterized by severe behavioral abnormalities across all primary areas of functioning. Its onset is often early; it generally makes itself known by the age of two and one-half. It is not a single disease entity but is instead a syndrome defined by patterns and characteristics of behavior; it, therefore, most likely has multiple etiologies rather than a single causative factor. Autism is not fully understood and thus is controversial with respect to diagnosis, etiology, and treatment strategies.