A-checks, Annuals, heavy D-checks etc are all carried out on the aircraft. The Pilot gets a Medical every year and maybe 8 hours in the Sim to check their physical health and their skills level. Nowhere is there a check-up "from the neck up".
We standardise our Aircraft, we standardise our SOPs so why not the same for Pilots? Nobody is trained to spot the clinical indicators in their colleagues and thus the easiest solution would be to fire anyone who is in any way 'different'. That should thin the numbers down a bit.
Surely there is a better idea out there somewhere???