If not even the cockpit colleagues sitting next to him get any warning right before I doubt that a psychiatrist can give guarantees. The 4U pilot back then deliberately split up his issues and met different doctors to hide the size of his only known to him problems.
Should all mental illnesses be blocked now, including pilots having suffered only for limited periods? Just to be on the safe side?
On the other hand what does it mean for teamwork, trust and safety culture? Will this bring us the single pilot cockpit with remote surveillance and some AI-master check for "plausible" flight operations?