Many of my clients write on their intake forms Depression and there's others that don't tell me and look a little sheepish when I ask them if they have tendencies to get depressed. You see I can tell by the links I get in a session. Many people with depression will have some very strong "beliefs" in the sub conscious mind.
Things like: I'm worthless.
I'm not worthy to be loved.
I don't deserve to be loved.
I don't need to love and respect myself.