there have literally been suicides during captain upgrades. And even after making it through, some elect to bid back to F/O rather than accept the pressure that comes from sitting there at night over an ocean with hundreds onboard; thinking of all the possible things that can go catastrophically wrong, knowing that for many of them there is no procedure in the book, realizing that legally and morally you're the final authority for what will be done to deal with anything that happens, accepting that you will be held ultimately responsible for any outcome, and having the self-confidence to believe that no matter what happens you'll manage to get it right - not horribly wrong.
- from where I see it, some pilots in that company are probably in the wrong job. Worrying indeed. Which airline please?