alt Hacker NewsThere's a perfect example of "highly regulated and controlled industries" in which people no longer self-report: aviation.
Pilots do not (or no longer) self-report mental illness at the same frequency because it effectively destroys their lives and career. One paper of many describing this phenomenon: https://pmc.ncbi.nlm.nih.gov/articles/PMC11302551/
An article, one of many: https://www.reuters.com/investigations/if-you-arent-lying-yo...
If you have any pilot friends in commercial aviation, you can just talk to them as well.
Airlines cannot try to put systems in place to deal with the issues? This isn't just about individuals but also organisations. You have to believe that organisations would also want to hide things even if mandated and incentivised otherwise.