WASHINGTON - In what could prove to be one of their most far-reaching decisions, psychiatrists and other specialists who are rewriting the manual that serves as the nation's arbiter of mental illness have agreed to revise the definition of addiction, which could result in millions more people being diagnosed as addicts and pose huge consequences for health insurers and taxpayers.
The revision to the manual, known as the Diagnostic and Statistical Manual of Mental Disorders, or DSM, would expand the list of recognized symptoms for drug and alcohol addiction, while also reducing the number of symptoms required for a diagnosis, according to proposed changes posted on the website of the American Psychiatric Association, which produces the book.
In addition, the manual for the first time would include gambling as an addiction, and it might introduce a catchall category -- "behavioral addiction, not otherwise specified" -- that some public health experts warn would be too readily used by doctors, despite a dearth of research, to diagnose addictions to shopping, sex, Internet use or playing video games.
Part medical guidebook, part legal reference, the manual has long been embraced by government and industry. It dictates, among other things, whether insurers, including Medicare and Medicaid, will pay for treatment.
The broader language involving addiction, which was debated this week at the association's annual conference, is intended to promote more accurate diagnoses, earlier intervention and better outcomes, the association said. "The biggest problem in all of psychiatry is untreated illness, and that has huge social costs," said Dr. James Scully Jr., chief executive of the group.
But the revisions in the manual, scheduled for release next May, have provoked controversy similar to concerns previously raised about proposals on autism, depression, bipolar personality disorder and other conditions. Critics worry that changes to the definitions of these conditions would also sharply alter the number of people with diagnoses.
While the association says that the addiction changes will lead to health care savings in the long run, some economists say that 20 million substance abusers could be newly categorized as addicts, costing hundreds of millions of dollars in additional expenses.
"The chances of getting a diagnosis are going to be much greater, and this will artificially inflate the statistics considerably," said Thomas Babor, a psychiatric epidemiologist at the University of Connecticut who is an editor of the international journal Addiction. Many of those diagnosed under the new guidelines would have only a mild problem, he said, and scarce resources would be misdirected. "These sorts of diagnoses could be a real embarrassment," he said.
The scientific review panel of the psychiatric association has demanded more evidence to support the revisions, but several researchers involved with the manual have said that the panel is not likely to make significant changes to their proposal.
The controversies about the revisions have highlighted the outsize influence of the manual, which brings in more than $5 million annually to the association and is written by a group of 162 specialists in relative secrecy. While other medical specialties rely on similar diagnostic manuals, none have such influence.
Many scholars believe that the new manual will increase addiction rates. A study by Australian researchers found, for example, that about 60 percent more people would be considered addicted to alcohol under the new standards. Association officials expressed doubt, however, that the expanded definitions would sharply increase the number of new patients, and they said that identifying abusers sooner could prevent serious complications and expensive hospitalizations.