This [1] is specific to the U.S. but you should get advise from a lawyer and not good intention folks here on HN. Sorry I don't know a labor law attorney. You could probably call the department of labor for the state your company's headquarters resides in. They could tell you if you have a case so you don't spend money on a lawyer unless it makes sense to do so. They would also know if that company has a history of complaints.

[1] - https://www.eeoc.gov/laws/guidance/depression-ptsd-other-men...