The diagnostic merry-go-round is incredibly frustrating. It's especially hard to wait for another appointment, another referral, another opinion, when you feel that the opportunity to help a child is slipping away with every passing day.

It might seem that categorization doesn't do much for patients in the here and now, but it's actually a very important task. A great deal of information is now available about helping people with ASDs, but there are such large differences between people on the spectrum that one-size-fits-all treatments are a mistake. It could be that people with one subtype will respond amazingly well to a particular medication, whereas others do not. Another subtype may respond to a special diet, whereas others do best with other therapies.

Incorrect diagnosis, however, can lead to incorrect-or even harmful-medical treatment.

Strategies and medications that work with specific symptoms can be used across the spectrum, no matter what subtype a person has been diagnosed with. For example, if a child with Asperger's syndrome is repetitively hitting herself in the head to the point of injury-a behavior more common in people with autistic disorder-methods used to stop this activity in more impaired autistic people might be just the thing to try. Getting the right diagnosis is important, but when it comes to treatment, you have to look at the person and his or her actual symptoms, not just the label.

Today's labels are also far too general. Each person with an autistic spectrum disorder diagnosis is neurologically impaired in one or more ways, but other systems may be unaffected. The degree of impact can also vary from mild to severe. For example, one person may have a severe speech delay but only mild social deficits, whereas another may be unable to form social attachments at all but may have relatively normal speech patterns.

As you read through these descriptions, you may notice that only parts of these diagnoses apply. A child may have the kind of topic fixations you'd expect with Asperger's syndrome, for instance, but also have a significant speech delay. Unless a person meets all the criteria for one of the specified ASDs, proper practice is to place him or her in the PDD-NOS (or atypical autism/autistic spectrum disorder) category.

Doctors and other professionals also use terms such as "high functioning" and "low functioning" to distinguish between people with autistic disorder. Most clinicians define "low functioning" autism as being nonverbal, having some degree of mental retardation, and perhaps having "difficult" behaviors or problems with toileting and other basic self-care skills. Most clinicians define "high functioning" autism as having an adequate amount of functional speech or the ability to use some other method of communication, some social ability, and at least basic self-care skills-although another clinician might call this picture PDD-NOS. There is no set definition for these terms, so if you are not sure what they mean, ask the person who is using them.

Finally, someone may start out with one diagnosis, such as autistic disorder, and end up with another one several years later when new symptoms emerge or old ones disappear. In many cases a very young child diagnosed with autistic disorder later "moves up" to PDD-NOS, atypical autism, or even no ASD diagnosis at all. Sometimes the first diagnosis was simply wrong, but other times the person has made truly-remarkable progress. That's what parents and professionals are all hoping for, and, with luck, studying these cases can show the way to that goal.

One family's long journey toward diagnosis

One family's long journey toward diagnosis took four years of trekking from doctor to doctor. Seven-year-old Joshua was given the following diagnoses:

• PDD-NOS. "The psychologist who gave this diagnosis said he'd probably never be able to live independently," says his mother, Krista.

• Disturbed. "The HMO child psychiatrist who gave this 'diagnosis' had white plastic bags full of sweets all over his office floor," Krista notes, with more than a touch of residual ire in her voice.

• Severe communication disorder, ADHD, and possible Tourette's Syndrome. "The developmental pediatrician and neuropsychologist at Children's Hospital gave this diagnosis, saying the PDD was wrong, that they'd seen specialized cases like Joshua's enough to know," Krista says.

• Rolandic epilepsy.

• Receptive and expressive language aphasia, central nervous system dysfunction, and ADHD.

In the past four years, Joshua has been through many medication trials, including stimulants, anti-depressants, anti-psychotics, and other drugs, none of them particularly helpful. He has undergone tests for allergies, metabolic disorders, chromosome abnormalities, hearing problems, and seizures.

Joshua sees a speech therapist, an occupational therapist, an adaptive PE specialist, and a behaviorist, and is taught by a special education teacher. He attends school in a mainstream second-grade class. He has been variously described as intelligent, easily distracted, obsessional, unusual, sweet-natured, and overly emotional.

Aside from the extreme attentional problems, the most difficult thing to deal with is his extreme variability. On good days, he does everything well: reads well, talks well, takes disappointment well. On bad days, he can't do anything. He can't talk, he can't read, he can't tolerate frustration, he can't perform at all. Everyone who works with him knows this is a child with a great deal of potential who presents different facets of himself as puzzles that are unresolved and unaccounted for, bewildering. --Krista, mother of seven-year-old Joshua

How do you label a child like Joshua? It isn't enough to enumerate the symptoms and then say, "let's just think of him as Josh."

As another parent said about his son, Jeremy:

What does having "Just Jeremy" do for my son? Are there schools for "Just Jeremy?" Is anyone developing medications for "Just Jeremy?" I do see him as an individual first--he's my son. But the rest of the world can't, and won't. I want to make sure he gets as much help as we can get him. --George, father of six-year-old Jeremy (diagnosed PDD-NOS)