Different types of autism

The “autism spectrum” describes a set of developmental delays and disorders that affect social and communication skills and, to a greater or lesser degree, motor and language skills.1 It is such a broad diagnosis that it can include people with high IQs and mental retardation. People with autism can be chatty or silent, affectionate or cold, methodical or disorganized.

Until May 2013, official diagnoses within the autism spectrum included 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. The term—and the diagnosis—was removed from the diagnostic manual in 2013, but virtually everyone in the autism community continues to use it because of its usefulness in describing a very specific group of people.

These difficulties become more obvious as they get older and social expectations increase. Because people with Asperger syndrome are often very intelligent – but “quirky” – the disorder is sometimes nicknamed “geek syndrome” or “little professor syndrome.”

Key Points:

• Asperger syndrome is no longer a valid diagnosis
• Asperger syndrome was and is still often used to describe people with “high functioning” autism2
• Most people with the symptoms of Asperger syndrome are of normal or above normal intelligence with strong verbal skill and significant difficulties with social communication
• Many people with Asperger syndrome have significant sensory challenges
• People with the symptoms of Asperger syndrome are now considered to have Level 1 Autism Spectrum Disorder

The term “mild autism” is not an official diagnosis. It’s simply a more descriptive term than “Asperger syndrome” or “autism.” Generally speaking, when people use the term mild autism they are referring to individuals whose symptoms fit an autism spectrum diagnosis, but who has strong verbal skills and few behavioral issues.

Key Points:

• Mild autism is essentially similar to or identical to Asperger syndrome
• People with mild autism may be difficult to recognize until they are under stress or coping with complex social situations
• Most people with mild autism are now considered to have Level 1 Autism Spectrum Disorder

Like “mild” autism, high functioning autism (sometimes shortened to HFA) is a made-up term that’s become more and more commonly used. At one point (before 2013), the term was used to distinguish “autism” from “Asperger syndrome.”

The official distinction made by practitioners before 2013 was that people with HFA had or have speech delays while people with Asperger Syndrome have normal speech development. Of course, these days there IS no Asperger syndrome, making the distinction moot.

Key Points:

• High functioning autism, like mild autism, is similar to Asperger syndrome and would now be termed Level 1 Autism Spectrum Disorder
• Unlike people who were diagnosed with Asperger syndrome, people with HFA developed language slowly or idiosyncratically
• Like Asperger syndrome and mild autism, HFA is a real and significant disability which can lead to challenges in managing social situations, school demands, work expectations, or recreational activities.

“Pervasive Developmental Disorder Not Otherwise Specified” is a mouthful of words that, until 2013, were used to describe individuals who didn’t fully fit the criteria for other specific diagnoses but are nevertheless autistic. Because there is no easy way to define the symptoms of PDD-NOS, which may range from very mild to very severe, the diagnostic category no longer exists, though a new diagnosis, Social Communication Disorder, may become a similar “catchall” category.3

Key Points:

• As of 2013, PDD-NOS is no longer a valid diagnosis
• PDD-NOS was a “catchall” for disorders with autism-like symptoms that didn’t fit the full criteria for
• People with PDD-NOS could have mild or severe symptoms
• Those people who were diagnosed with PDD-NOS prior to the DSM-5 will now have an autism spectrum diagnosis and may be diagnosed at Level 1, 2, or 3 depending on the severity of symptoms

Severe autism is not an official diagnosis; instead, it is a descriptive term along with profound autism, low functioning autism, and classic autism.

Key Points:

• Severe autism is usually diagnosed as Level 3 Autism Spectrum Disorder
• Severe autism is extremely challenging and may include aggression and other difficult behaviors
• Most people with severe autism never gain meaningful use of spoken language
• Some people with symptoms of severe autism do gain the ability to communicate through signs, picture boards, or other means

Rett syndrome is a genetic disorder that primarily affects girls.4 It is the only one of the former autism spectrum disorders that can be diagnosed medically (so far); as of May 2013, it is no longer included in the Autism Spectrum.

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.

Key Points:

• Rett syndrome is no longer part of the autism spectrum
• Rett syndrome is a genetic disorder which can be medically diagnosed
• Rett syndrome impacts only girls
• Symptoms of Rett syndrome include social communication challenges and the loss of purposeful use of one’s hands

The broad autism phenotype includes those people with the merest touch of autism. This is sometimes described as having “shadow symptoms.” These sub-clinical symptoms can include social awkwardness, anxiety, a preference for sameness and routine, and an unusual degree of discomfort around bright lights, loud noise, and other sensory “assaults.”

Such mild symptoms, which are recognizable but which do not significantly impair daily functioning, are common among family members of people with full-blown autism.5 Is this really autism? Or just a personality type? As with many issues related to autism, it depends on whom you ask. Either way, it is often helpful for people with such symptoms to seek help with building social communication skills and coping with sensory challenges.

Key Points:

• There is a “broad autism phenotype” which includes people with milder autism-like symptoms
• Many people with such symptoms have children or other relatives on the autism spectrum
• Many of the treatments available for autism can be helpful for people with milder versions of the same symptoms