p.s 2plus, at least if the condition was with the pilot the whole time there is more chance of it beimg observed before he/she has 100+ souls in his/her care.
Possibly. I think it's also just as possible it may still go unnoticed, which is what appears to have been partly the case in this tragedy. What signs do you look for in someone to check if they're in the right frame of mind to operate? When would you pull them aside for a chat? Briefing? Before leaving the flight deck? Does one need to be suffering from a long-term underlying condition before they one day decide to look for a release, perhaps from the effects of a more recent stressful event?
It's not uncommon for sufferers of mental illnesses such as depression to not give any "tells". If this bloke did indeed have "issues", then from what I've seen of the footage, there were at least some who were close to him yet found it completely out of character for him. I heard he took a break from training. Obviously he was later found fit to continue. Could happen to any of us, new recruit or veteran.