Autism is a spectrum disorder. It manifests itself differently in each and every individual who suffers from it, whether the profoundly or mildly autistic. Its many different faces result from factors that science simply doesn't understand, that likely result from the complex underlying causation of autism. There are several different diagnoses that are medically available within the autism spectrum:

A note on medical diagnoses:

I encourage parents to work with the professional medical community to obtain a diagnosis for your child. It is of crucial importance to obtaining services you need for your child. However, don't think a diagnosis is the end of the road, or relieves you of obligations as a parent to take primary care of your child. A diagnosis is simply a tool required in modern medicine. Be cautious about this tool.

A diagnosis is an attempt to cluster people with similar symptoms within a label. Diagnoses are useful medically because they allow doctors to tell patients what the diagnosis is, which often calms everyone down. They are useful for the insurance industry, so they can set policies related to reimbursements. They are useful for the pharmaceutical industry, so they can market drugs to people based on the drugs' approval to treat the diagnosis.

However, diagnoses involve a vast oversimplication of reality. No two people have autism in exactly the same way. Diagnoses tend to blind people to the reality of the situation. They focus on the specificity of the condition, the 'common' symptoms recognized by the medical community, while ignoring the issues the parents deal with at home. Also, when parents are seeking a diagnosis for their child, the world is essentially on hold until the diagnosis is made. Everyone is powerless, and enormously anxious, during this period which averages 18 months. Progress essentially stalls during this period.

This delay occurs largely because of the complexity and subjectivity of the condition and doctors' reticence to apply a label that could damage the child's future. During that time, precious seconds are ticking that could be used helping the child mitigate their symptoms. Diagnoses are particularly challenging related to psychological disorders, and in particular spectrum disorders. And, diagnoses of specific conditions often take off the table treatment and coping options that we know are beneficial for pretty much all conditions, like adequate sleep and a healthy diet, and replace those options with medications that have been created to treat the diagnosis. Be careful with medications. I address them on my Coping with Autism page.

Low Functioning / Classic Autism

Low functioning autism is the condition that most people think of when they think of autism. It is also called profound autism or classic autism. The children with this diagnosis, and the adults they become, are those who are most troubled by this disorder. The symptoms listed on the Symptoms of Autism page are tailored for this group of individuals. It is in this group that mental retardation is most often seen, as well as the complete loss of communication.

Pervasive Developmental Disorder - Not Otherwise Specified (PDD-NOS)

PDD-NOS is the most common diagnosis on the autism spectrum, and is given when some, but not all, of the symptoms associated with classic autism are present. Perhaps the child started having difficulties at a much later age than others on the spectrum. Or they may have the same challenges — for example, they may be oversensitive to their surroundings — but not to the extreme that others on the spectrum do. Consequently, those with PDD-NOS are sometimes thought to have a "milder" form of autism, though this may not be technically true. One symptom may be more minor, while another may be worse.

Childhood Disintegrative Disorder (CDD)

CDD is a relatively rare condition in which young children develop normally until age 3 or 4, but then demonstrate a severe loss of social, communication and other skills. Doctors sometimes confuse this disorder with late-onset autism because both conditions involve normal development followed by significant loss of language, social, play and motor skills. However, autism typically occurs at an earlier age. There's also a more dramatic loss of skills in children with childhood disintegrative disorder and a greater likelihood of mental retardation.

Asperger's Syndrome

Asperger's Syndrome is a diagnosis for individuals who are much more functional than those with low functioning autism. Those who are diagnosed lack the extreme tendencies towards withdrawal seen in classic autism - however, they are still often isolated due to their problems with social interaction. There is some debate as to whether Asperger's constitutes its own discrete disorder, or it just a high functioning form of autism. I ascribe to the latter position.

Children with Asperger's Syndrome find it difficult to identify and express their feelings, just like those with classic autism. They find it challenging, even impossible, to connect with others, often don't hold eye contact and have trouble reading other people's faces and gestures. Many kids flap their hands, a behavior often associated with classic autism; speak without much emotion (or have otherwise unusual speech patterns); need to follow schedules rigidly or else the world feels out of control, and are intensely, even obsessively, interested in one specific subject, so much that they become veritable experts in that field. They also exhibit sensitivities to various stimuli, from sounds to clothing to food items.

In contrast to Low Functioning Autism, children with Asperger's Syndrome usually don't show any signs of major cognitive difficulties — their IQ falls in the normal or even superior range—and they exhibit few, if any, delays in speaking. They also generally hit most of their milestones within reasonable time periods. To many, they may seem just like other children but not quite — socially awkward in a manner that's not easily understood.

Moreover, persons with Asperger's Syndrome often have areas of extreme competency that are beneficial in their professional careers. Persons with Asperger's are known to be supreme puzzle workers and problem solvers. They often have tremendous mathematical and analytical skills. They are also known for competency with spatial processing. Simon Baron Cohen often terms autism as the 'extreme male syndrome', and persons with Asperger's are often sufficiently high functioning to be able to take advantage of the beneficial characteristics of the extreme male brain.

The Broad Autism Phenotype

There are many individuals in the world, including me, who share characteristics with persons on the spectrum, but who are not 'disordered' according to the diagnostic criteria. They may have a portion of the negative symptoms of autism, like sensory processing abnormalities, or eye contact avoidance, or problems with reading body language. And, they may share some of the positive aspects of the autistic spectrum, like strong skills in systemitizing or running spreadsheets. In My Theory, those on the broad autism phenotype share a neurological profile with those on the spectrum, but have not been pushed off the edge into being disordered.