"A sad soul can kill you quicker, far quicker, then any germ" John Steinbeck
This was quoted by Dr. Spencer Reid (Matthew Gray Gubler) on the show Criminal Minds.
For people suffering from depression or any kind of mental illness, I think the quote is so real, so true.
If you know someone who is depressed, shut-in, or just lonely, why don't you give them a call, drop them a line or even invite them out for lunch. They may say no, but I guarantee you, they'll appreciate it.