How Is Autism Diagnosed?

It's not unusual for parents to notice that there is something 'odd' or 'different' about their child long before anyone else, but most children with autism aren't diagnosed until they are 2 to 3 years old - or much later. Autism isn't an easy disorder to diagnose. In many cases, particularly in mild cases, there's a broad gray area between a child who has mild autism (often simply called 'some autistic tendencies) and a child who simply doesn't fit the usual behavioral and social norms. And in fact, many children who would simply have been considered 'a little peculiar' are diagnosed as autistic these days.

There are currently no easy tests for diagnosing autism, though those may be on the way as researchers identify genetic markers for autism. Currently, though, there's no blood test, no MRI, no medical way to tell if a child has autism. Instead, doctors rely on observations of a child's behavior, communication skills and abilities and developmental level to arrive at a diagnosis.

Your doctor may suggest medical tests to rule out other disorders, though, since many of the symptoms and behaviors associated with autism are also symptoms of other disorders. One of the disorders in the autism spectrum, for instance, is Rett's Syndrome, for which there is a medical test that is 80% accurate. Other medical problems that could account for some of the symptoms of autism are hearing loss and mental retardation.

Ideally, a child suspected of having autism should be evaluated by a multi-disciplinary team consisting of specialists in neurology, psychology, developmental pediatric, speech and language pathology and other professionals who are familiar with autism.

You will probably be asked a lot of questions about your child's behavior. A psychologist may sit down with you and have you fill out assessment charts and checklists to help pinpoint particular behaviors and symptoms. You may be given checklists to fill out. These are all called 'instruments', and they can help your child's doctor more accurately diagnose any problems that your child may be having. Some of the instruments used to diagnose autism include the CARS (Childhood Autism Rating Scale), the GARS (Gilliam Autism Rating Scale), the CHAT (Checklist for Autism in Toddlers), the BRIAC (Behavior Rating Instrument for Autistic and Other Atypical Children) and the PIA (Parent Interviews for Autism).

Your child's diagnosis may read (or a doctor may tell you) that your child 'meets the criteria for autism'. The Diagnostic and Statistical Manual for Mental Disorders Fourth Edition, usually called the DSM IV, contains a list of criteria for determining whether a child has autism. It consists of two lists of behaviors that a child with autism may exhibit. A child who exhibits more than six symptoms from the list, including at least two from the first list, meets the criteria for autism, as long as the symptoms began before the age of three and are not part of another syndrome or disorder that the child has.