Autism is a spectrum that encompasses a wide continuum of behavior.
Core features include impaired social interactions, impaired verbal and nonverbal communication, and restricted and repetitive patterns of behavior. The symptoms may vary from quite mild to quite severe. In the past, autism was thought to be a mental illness caused by bad parenting. This destructive idea has been disproved. We now know autism to be a physical condition linked to abnormal biology and neurochemistry in the brain.