The trustees made the final decision on what proposals made the cut; recommendations came from experts in several task-force groups assigned to evaluate different mental illnesses.
Board members were tightlipped about the update, but its impact will be huge, affecting millions of children and adults worldwide.
The manual "defines what constellations of symptoms health care professionals recognize as mental disorders and more importantly . . . shapes who will receive what treatment," said Mark Olfson, a Columbia University psychiatry professor who was not involved in the revision process. "Even seemingly subtle changes to the criteria can have substantial effects on patterns of care."
The manual also is important for the insurance industry in deciding what treatment to pay for, and it helps schools decide how to allot special education.
The guidebook's official title is the Diagnostic and Statistical Manual of Mental Disorders. The new one is the fifth edition, known as the DSM-5. A 2000 edition made minor changes, but the last major edition was published in 1994.
Expected changes include formally adopting a term for children and adults with autism - autism spectrum disorder, encompassing those with severe autism, who often don't talk or interact, and those with mild forms including Asperger's. Asperger's patients often have high intelligence and vast knowledge on quirky subjects but lack social skills.
Some Asperger's families opposed the change, fearing their children would lose a diagnosis and no longer be eligible for special services. And some older Asperger's patients vowed to continue to use the label.
But experts say the change won't affect the special services available to this group.
Catherine Lord, an autism expert at Weill Cornell Medical College who was on the psychiatric group's autism task force, said anyone who met criteria for Asperger's in the old manual would be included in the recommended new diagnosis.
One reason for the recommended change is that in some states and some school systems, children and adults with Asperger's receive no services or fewer services than those given an autism diagnosis, she said.
Other proposed changes include:
A new diagnosis - disruptive mood dysregulation disorder, which critics argued would medicalize kids' normal temper tantrums. Supporters said it would address concerns about too many children being misdiagnosed with bipolar disorder and treated with powerful psychiatric drugs. Bipolar disorder involves sharp mood swings from feeling sad and depressed to unusually happy or energetic. Affected children are sometimes very irritable or have explosive tantrums. The new diagnosis would be given to children and adults who can't control their emotions
Eliminating the term dyslexia, a reading disorder that causes difficulty understanding letters and recognizing written words. The term would be encompassed in a broader learning-disorder category.