1 - If you don't have it you don't understand how difficult it can be.
2 - Sometimes lack of knowledge about it does not mean it doesn't exist. Players in those countried develop other issues, Kambli is a great e.g. that comes to mind.
3 - There is this belief that you can tough it out, don't be week etc. Its not that simple
On most days you could feel down but believe you can cope, amount it to pressure of life/situation etc but then there are some days where you cannot control it or manage it or hide it, takes a bit to recover from it and everyone recovers differently with varying amount of time. You don't know what is going to trigger an episode, atleast not early or what the symptoms are. Most people are even embarrased to talk about it let alone go see a professional but it needs to be done and takes a lot of courage, most days you feel like a failure in one way or another, need a very strong support structure around (internal and external). Accepting help is difficult, sometimes people trying to help may seem like your worst enemies and others might not have a clue what they are talking about but when the clouds clear you feel stronger and happier to have had the fortune being around well wishers who care.
I feel for Trott, I hope he gets all the help he needs and more. You have to fight your demons, not easy but that is the only solution (with help)