Find out more about the different types of autism and what a person with that diagnosis is likely to look like.
The "autism spectrum" describes a set of developmental delays and disorders which affects social and communication skills and, to a greater or lesser degree, motor and language skills. It is such a broad diagnosis that it can include people with high IQ's and mental retardation - and people with autism can be chatty or silent, affectionate or cold, methodical or disorganized. "Autism Spectrum" is also another, less formal term to describe the Pervasive Developmental Disorders.
Official diagnoses within the autism spectrum are autistic disorder, pervasive developmental disorder not otherwise specified (PDD-NOS), Asperger syndrome, Childhood Disintegrative Disorder and Rett Syndrome.
Asperger syndrome describes individuals at the highest-functioning end of the autism spectrum. Unlike other autism spectrum disorders, Asperger syndrome is often diagnosed in teens and adults. People with Asperger syndrome generally develop spoken language in the same way as typically developing children, but have a tough time with social communication. These difficulties that become more obvious as they get older and social expectations rise. Because people with Asperger syndrome are often very intelligent - but "quirky" - the disorder is sometimes nicknamed "geek syndrome" or "little professor syndrome."
Like "mild" autism, high functioning autism (sometimes shortened to HFA) is a made-up term that's become more and more commonly used. HFA is a tricky term, because it can be hard to distinguish a person with HFA from a person with Asperger syndrome. The official distinction is that people with HFA had or have speech delays, while people with Asperger Syndrome have normal speech development. But there may also be very real differences in terms of social awareness, personality characteristics, and other traits. The jury is still debating the fine distinctions.
"Pervasive Developmental Disorder Not Otherwise Specified" is a mouthful of words that are often applied to people on the autism spectrum. It describes individuals who don't fully fit the criteria for other specific diagnoses, but are nevertheless autistic. Unfortunately, there is no easy way to define the symptoms of PDD-NOS, which may range from very mild to very severe. As a result, the term is rarely used outside of practioners' offices. Most parents, therapists and teachers prefer to use more descriptive (though less official) terms to describe their children, students and patients with PDD-NOS.
Severe autism is officially termed autistic disorder. It goes by many other names, though, including profound autism, low functioning autism, or classic autism. People with autistic disorder are often non-verbal and intellectually disabled, and may have very challenging behaviors.
Rett syndrome is a genetic disorder that affects only girls. It is the only one of the autism spectrum disorders that can be diagnosed medically (so far). Girls with Rett syndrome develop severe symptoms including the hallmark social communication challenges of autism. In addition, Rett syndrome can profoundly impair girls' ability to use their hands usefully.
If Asperger syndrome is considered "mild" autism, then the broad autism phenotype includes those people with the merest touch of autism. Is this really autism? Or just a personality type? As with many issues related to autism, it depends on who you ask.