a heroic dose of psilocybin is very likely to make you confront the source of depression.

Whatever there is under the surface affecting you, it certainly isn't going to hide during a heroic trip. Quite the contrary, it gets amplified, taken to it's extreme - and if you accept it, you'll be shown the other side. And it starts loosing its power over you.

The "source" or your "problem" likely isn't what you thought it was at first either, according to a friend.

So it's not a drug that will make the pain go away. It will show you things through experience, which is a powerful way of learning.