For ADHD, the definition is being broadened, meaning the disorder could be diagnosed in more children. In the case of autism, the opposite is true.

The new criteria are among the changes that will be released with the publication this weekend of the long-awaited guidebook that psychiatrists and other mental health clinicians use to diagnose mental disorders. It’s the first major update in nearly 20 years. The 947-page tome by the American Psychiatric Association adds some new disorders, broadens criteria for existing ones and tightens them for other illnesses.

The highly controversial decisions involved in producing the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders, or DSM-5, have a potentially broad impact: They can affect which services children receive in schools, what treatments patients receive from doctors and even how people are viewed by society.

Experts involved in the guidebook say the changes will give clinicians greater precision in diagnoses and treatments. Critics counter that the new language will make it too easy to turn the stresses of ordinary life into mental illnesses, resulting in some people getting too much treatment.

For the first time, for example, someone who experiences severe grief after the death of a loved one — including extreme sadness, decreased appetite, fatigue and the inability to sleep — could receive a diagnosis of major depressive disorder. A patient whose mental decline is mild, but seems more serious than normal, could receive a diagnosis of mild neurocognitive disorder, which is new to the DSM-5.

This undated image shows the cover of the revised American Psychiatric Association’s guidebook of mental disorders being released in May 2013. It is the manual’s first major update in nearly 20 years. (AP)

Also new: Someone who repeatedly overeats could get a diagnosis of binge-eating disorder. A person who allows possessions to fill up the home could have hoarding disorder. The manual also spotlights conditions, such as Internet gaming disorder, that merit further research before being included as official diagnoses.

Impact on services

The handbook plays a big role in American society. It determines which diagnostic codes medical professionals use for specific patients and can affect whether health insurance pays for treatment. The DSM’s wording also can dictate which social services people are entitled to.

Long before the DSM-5’s official release, scheduled for Saturday at the psychiatric association’s annual meeting in San Francisco, the publication drew intense fire.

Thomas Insel, director of the National Institute of Mental Health, the largest mental health research organization in the world, set off a furor when he said the manual lacked validity. He said the NIMH would shift its research away from the DSM categories — and their symptom-based criteria. Instead, new research would focus more on areas such as the biology of brain circuits and the behavior they produce, as well as emerging clinical data.

“While DSM has been described as a ‘Bible’ for the field, it is, at best, a dictionary, creating a set of labels and defining each,” he wrote in a blog post.

For example, in major depression, one symptom is anhedonia, the loss of pleasure in things someone used to enjoy. But that loss also can refer to someone’s “willingness to go get things you like,” and those are two different brain circuits, said Bruce Cuthbert, coordinator of the NIMH’s new research project.

So even if people have the same symptom of depression and receive the same diagnosis, what they really suffer from may be different. Treatment doesn’t work for everybody, he said.

Defending the guidebook

David Kupfer, the chairman of the task force that oversaw the development of the revised guidebook, said the 31 members of the group spent enormous amounts of time reviewing clinical and research data collected over the past 20 years and weighing every potential change.

He rejected criticism that the changes would increase the number of people who receive diagnoses of mental disorders, saying the number of disorders is essentially the same. Some new ones were added because research and public health data indicate they are “ready for prime time,” he said in an interview.

“When all is said and done, we’re not concerned that we’ve created many new disorders . . . or that we’re going to add to the number of people who will be diagnosed with mental illness,” Kupfer said. But he added that clinicians must stick to the precise criteria in the manual in making diagnoses.

He also said that experts working on the updated publication sought to pay more attention to early signs of the country’s most serious public health problems, such as Alzheimer’s disease, the fifth-leading cause of death among people 65 and older.

One of the new disorders included in the manual is mild neurocognitive disorder, which could be an early sign of Alzheimer’s, Kupfer said. The diagnosis might be applied to someone with increased forgetfulness and difficulty with day-to-day activities, such as paying bills and managing medications.

“I don’t think we are talking about people who are not finding their keys,” Kupfer said. “You would be talking about memory changes that could be quite significant.”

That doesn’t mollify critics such as Allen Frances, who chaired the task force that produced the DSM-4 and wrote a book assailing the DSM-5 as opening the door to designating normal behavior as a disorder.

“Old folks like me who are forgetful could be classified as having mild neurocognitive disorder,” he said.

In the case of ADHD, or attention deficit hyperactivity disorder, the new criteria allow children to receive the diagnosis if they show signs of the disorder before age 12 — instead of the previous age of 7.

“That is expanding the definition of ADHD. Now they’re saying you have many further years to demonstrate these symptoms,” said Avram H. Mack, president of the Washington Psychiatric Society and a psychiatry professor at Georgetown University’s School of Medicine who evaluates children for developmental disorders.

By contrast, several previously distinct autism-related disorders, such as Asperger’s syndrome, were consolidated into one diagnosis of autism spectrum disorder.

But what is unknown is at what point on that continuum the payor or school system will recognize it as a clinically significant condition,” Mack said. “We don’t know how schools will react to that.”

In addition, the changes in the criteria also mean that many children whose “autistic-ness” included mostly problems with communication without the presence of repetitive behaviors may be reevaluated and perhaps receive a diagnosis of a communication disorder instead of an autism spectrum disorder, he said.

Some of those children probably would benefit from early intensive behavioral intervention, but it’s unclear whether clinicians will make that recommendation, said Geraldine Dawson, chief science officer of Autism Speaks, an advocacy group.

Sandhya Somashekhar and Alice Crites contributed to this report.