John Kerkorian, an employment partner with the Phoenix law office of Ballard Spahr, said that as many as one in four American workers could be protected from disability discrimination under new provisions of the Americans with Disabilities Act. He said the expanded ADA provisions also could create legal complications for employers.

Mr. Kerkorian said the new provisions expand the definition of disability to include emotional, respiratory, circulatory, neurological, and digestive problems. Workers can qualify as disabled and protected even if they don’t take medication or steps to mitigate their disability, he said.