It is good that you are concerned. Sometimes depression goes unnoticed. Mine did for a long time.

I don't know what you can do but i'll give it a punt.

Perhaps leave lying around on the fridge on on the table, pamplets about depression, ones that are aimed at young people. If he happens to pick one of these up and read it, he may think....geez this sounds like me....there are other people out there going through the same thing....maybe i should ask for help and take their advice.

If you have a whiteboard or chalk board, if not, maybe get one, a small one that you can hang up, you can use this to communicate with him, without being in his face, over-parenting or demanding that he open up. Try writing positive messages like "The strongest thing someone can do is to ask for help" or "A real man can cry and not feel ashamed" actually that may be a little corny, perhaps, "Tears are the outlet of the soul". He may think this is mushy, i'm not sure. But most likely he is a sensitive person, which is why he is depressed.

I really think this is good advice, my brother is like your son, he sits at the table and says barely anything. He doesn't want to cry, so he bottles it up or cuts on himself. It just shows he is senstive and perhaps hasn't had the best role model, no offence, for example his Dad. Sorry....is that you? Or are you his Mum? Anyway, every teenager has to learn how to express himself without being labelled a wimp, girl, cry-baby, geek, try-hard, or mummy's boy. I think that is what this is about.