Depression is real and so are mental health issues. Don't make fun of anyone's feelings if they share such things of their life with you. People think millions of times before confessing something like this. If they have taken this step of talking about it to you openly then surely you are someone whom they trust blindly. Don't laugh at them. Instead, talk to them and help them out. 'The Sorry Life' is a story of a girl named Anushka who suffered through all of it but never lost hope and came out of it bravely.