I've had to deal with depression off and on for a good chunk of my life. So I can say from personal experience that this is almost certainly not his problem. Depression, leading to suicidal thoughts and tendencies, causes small things to seem a lot worse than they really are. Your very mind messes with you, making you obsessed with how terrible things are and incapable of managing it healthily; so when some event triggers an emotional outburst, it only happens after a long period of things building up, many of which are not even related to that trigger.

It's good to know that people are getting him help. Because it isn't the show or some assholes on the internet that is affecting him, he's just sick, and like all sick people, he needs treatment to get better.

Suppose this is the reason why they don't develop background ponies. Unless they tread carefully mountains of fanfiction & fanon will crumble before the Word of God.

… which I'm all for! They should give Lyra a boyfriend!