I think PT is a microcism (sic) of the real world, slightly skewed, of course, since it is a pet site. I think there are alot of troubled people in the world, in general.

As to your comment re: being content, and around contented people....I would be willing to wager there are people in your immediate circle of friends that struggle/have struggled with depression. It isn't really the type of thing people say, "Hi, I am so and so, and I am depressed". You know? Of course, I could be wrong, but, I don't think so...