Unfortunately, the Americans with Disabilities Act (ADA) doesn't come with a laundry list of conditions that qualify as disabilities. So what about attention deficit disorder (ADD) or attention deficit hyperactivity disorder (ADHD)? Are they "disabilities"?
The answer: Maybe, maybe not. The deciding factor is whether the condition is severe enough to "substantially limit the employee's ability to perform one or more major life activities." The same is true with other conditions such as migraine headaches and carpal tunnel syndrome. Some cases may be covered by the ADA, and others won't. You must make a case-by-case determination based on the worker's demonstrated abilities.
Recent case: After being diagnosed with ADHD, James Whitlock was prescribed the drug Ritalin to help him concentrate at work. To accommodate his impairment, his employer let him build partitions around his work space and use a radio to block out background noise. Whitlock's problems at work persisted.
He ultimately quit and sued his employer for disability-based discrimination and harassment. He claimed, as is common among ADA plaintiffs, that his mental impairment substantially limited his ability to engage in the major life activity of "work."
But the court threw out his lawsuit, saying that even if Whitlock couldn't perform his current job, he wasn't "substantially limited" (as required under the ADA) because his ADHD didn't prevent him from performing many other jobs. (Whitlock v. Mac-Gray Inc., No. 02-2568, 1st Cir., 2003)
Final point: One unique twist to this case: Whitlock alleged the company created a "hostile work environment" due to his disability. Many employers think about harassment only in terms of race and sex. Make sure your company policies and training warn against all forms of unlawful harassment, including disability-based harassment.