......I read a short article some years ago now that suggested that 95% of humans suffer from depression sometime during their lives. We pilots are no different than the man on the street & I would be surprised if a good majority of 'pointy end drivers' didn't suffer some sort of depression on a regular basis. As long as it's recognized and managed then it can only lead to a safer environment in the cockpit.
Afterall you can make an A/C almost fool proof with numerous redundancy systems just in case but in the case of single pilot ops you only have a 'one heart' & ''one sane' pilot up front !:-)
Capt Wally:-)