If she has something that can be diagnosed, it can help with schooling in the U.S. (and probably elsewhere).
In the U.S. Federal law requires public schools to provide some forms of accommodations. Search for "section 504 of the Rehabilitation Act of 1973". Accommodations range from the trivial, like getting to sit up front in class or getting reminded to write down assignments, to things like getting an extra day for homework or getting access to remedial teaching or tutoring. Some of these could greatly relieve stress.
"My kid never even realizes that homework was assigned, and the teachers are not good enough about noting assignments online in a timely manner, so she's always late to turn them in or misses them completely, so she's failing her classes even though she gets A's in all the tests!" -- if you find yourself saying something like that, then you need some 504 meetings! An official diagnosis from a psychiatrist might not even be necessary, i don't know, but certainly a therapist might prove useful anyways in helping your child get more out of life.