The American Psychiatric Association sent shivers through the mental health community last week when it said it was re-examining its list of disorders and would be proposing a more narrow definition of autism, one that might exclude up to three-quarters of the cases that exhibit milder symptoms.

Understandably, parents and caregivers of autistic kids worried that the new definition might shut the door to expensive treatments for children who have been diagnosed with the condition in ever-greater numbers in recent decades.

In some ways, the adjustment is editorial. The APA is in the midst of updating the Diagnostic and Statistical Manual, the giant standard reference of mental disorders, where all mental illness is assigned universal definitions, for the first time since 1994. Often called the bible of psychiatry, the DSM is cited clinically in courts and by insurance companies to determine the extent of treatment that might be offered and is itself not without controversy.

In a mere 50 years it has gone from being a manual of just over 100 pages that defined 103 disorders to its current, fourth edition, that is 886 pages in length and lists 374 known mental disorders.

A Burnaby, B.C., boy with autism peers into his former elementary classroom. He is on a provincial waiting list for a care worker. (Canadian Press)

It also has the unenviable reputation of having been sharply criticized by two of the eminent practitioners who oversaw the DSM expansion in its earlier stages.

The textbook of the mind

"What's funny about the DSM, and critics of psychiatry always point this out, is that DSM-1 was a tiny little pamphlet and DSM-2 was bit bigger," says Jon Ronson, my guest this week on CBC Radio Day 6.

"By the time it got to DSM-4, it was just vast. It was bigger than the New Testament and the Old Testament and the Talmud all put together."

Ronson is a writer and documentary maker whose books The Psychopath Test and The Men Who Stare at Goats look closely at behaviour that defies the rational.

In The Psychopath Test, his most recent book, I thought I detected some skepticism about the DSM and its centrality in modern psychiatry. But his take is more nuanced than some.

It was DSM-4, the current, gargantuan edition that added Asperger syndrome as an autism-spectrum disorder in 1994.

Since then, the number of reported cases has exploded and the man who headed the task force that created DSM-4, Dr. Allen Frances, currently professor emeritus at Duke University, has been highly critical of his own work.

He told Ronson that the inclusion of Asperger was a mistake and he has also had some sharp advice recently for the task force working on DSM-5.

"Anticipate the worst. If something can be misused, it will be misused," Frances told National Public Radio in the U.S. "If diagnosis can lead to over-diagnosis and over-treatment, that will happen. So you need to be very, very cautious in making changes that may open the door for a flood of fad diagnoses."

False epidemics

Dr. Frances told Ronson that he and his associates had created three false "epidemics" — childhood bi-polar disorder, autism and ADHD.

But Ronson told me he doesn't fully go along with Frances.

"I looked at all three and out of the three, the only one I felt comfortable about [excluding] was childhood bi-polar disorder. That seemed quite open and shut," Ronson said. "Aspergers is a much more complicated thing."

Frances, it turns out, is not the only task force head who came to be critical of his edition of the DSM.

The third edition, DSM-3, published in 1980, was a kind of coming-of-age for the manual.

Recognizing the increasing use of the DSM outside of clinical situations, diagnoses were described in colloquial terms.

It was a time when mental disorders and illnesses were moving into popular understanding and the head of the task force then, Dr. Robert Spitzer, one of the most influential psychiatrists of his day, was credited with modernizing psychiatry and changing the way people think about mental illnesses.

In fact, he was the one who spearheaded the drive to remove homosexuality from being considered a mental illness. But he also came to believe that his edition of the DSM was flawed.

In 2007, Spitzer told journalist Adam Curtis, "What happened is we made estimates of prevalence of mental disorders totally descriptive without considering that many of these conditions might be normal reactions, which are not really disorders.

"I don't know if it's 20 per cent or 30 per cent [of all medicalized cases], but that's a considerable amount if it's 20 per cent."

Unscientific process?

As revolutionary as the DSM-3 would become, Spitzer's methods had an arbitrary feel and the science behind them has been questioned.

"There was very little systematic research, and much of the research that existed was really a hodgepodge — scattered, inconsistent, and ambiguous," Theodore Millon, one of the members of the DSM-3 task force, said in an interview in The New Yorker.

"I think the majority of us recognized that the amount of good, solid science upon which we were making our decisions was pretty modest."

As Jon Ronson tells it, "Robert Spitzer really hated Freudian psychotherapy," and so he gathered a bunch of like-minded people who just kept coming up with new conditions and checklists of symptoms.

"And that's how bulimia came to be invented, that's how ADHD came to be invented. Just this cacophony of voices, the loudest got heard the most."

Crossing a line

Given the history of how these manuals have been created, you can see how difficult the job of the DSM-5 task force will be. (It doesn't actually report until next year.)

Just changing the label, the category of a disease, that's all it takes to alter millions of lives.

If you're affected, it can seem capricious, arbitrary or cruel, familiar criticisms to the framers of the DSM.

Conversely, the information contained within its hundreds of pages may open a path to diagnosis.

For his part, Ronson thinks it's a valuable tool. "In an awful lot of cases a diagnosis and a label can only be a good thing."

For example, he says, a diagnosis can help a child with obsessive-compulsive disorder come to terms with "the incredibly intrusive, baffling, strange thoughts they were having," and then it can be treated.

That's certainly one of the reasons why the caregivers of people with Asperger syndrome have been so worried about its place in DSM-5.

The same for autism. Milder forms of the disease may end up being seen as a behavioral dysfunction instead of a real neurological condition.

And that can make a world of difference, a world defined by questions that mental health professionals are always asking. What is unusual but normal? What is chronic? What is treatable?