The Lord uses doctors to help heal us. The are an instrument of His. But it also makes a difference in how people react to someone in the middle of depression, and in the middle of being in that pit. People feel like saying those insensitive phrases, “Why so glum?", "Come on, get it together!", "Pull yourself up by your bootstraps!", "Get out of the pit you’re in. You’re a Christian". "You have all you need in Christ.” In this situation, the person battling depression is missing the very thing they need the most: the prayers of others. We criticize and speculate, and if we cease praying for those in a battle then we've missed the mark as Christians.
Do me this one favor, when you see someone in a state of despair, someone going through depression, or an emotional wreck... offer them a shoulder to cry on, a hug, a listening ear, a list of activities that may help them, phone numbers to doctors etc., but most importantly offer them your prayers! It will go a lot further than insensitive remarks! You are not alone!