Autism is not caused by bad parenting. Furthermore, no known psychological factors in the development of the child have been shown to cause autism. There are no medical tests for diagnosing autism. An accurate diagnosis must be based on observation of the individual's communication, behavior, and developmental levels. However, because many of the behaviors associated with autism are shared by other disorders, various medical tests may be ordered to rule out or identify other possible causes of the symptoms being exhibited.
Diagnosis is difficult for a practitioner with limited training or exposure to autism.
Sometimes, autism has been misdiagnosed by well-meaning professionals. Difficulties in the recognition and acknowledgment of autism often lead to a lack of services to meet the complex needs of individuals with autism. A brief observation in a single setting cannot present a true picture of an individual's abilities and behaviors. At first glance, some persons with autism may appear to have mental retardation, a behavior disorder, problems with hearing, or even odd and eccentric behavior. To complicate matters further, these conditions can co-occur with autism.