i don't have clinical depression but im guessing that if you do the best place to search is the NHS so i have found a link to the part of the NHS that deals with depression
anybody reading this thread who happens to suffer, or know somebody who suffers from this problem i hope that this helped you, and that you/they recover soon
Well from logic, and anti-depression medication, some symptoms would be lack of interest, suicidal thoughts(in severe cases), being tired, wanting to be alone, and sadness. I have ever been depressed, nor been around someone depressed, this is just from logic and depression awareness. You could always google some depression symptoms. I hope your friend goes to "normal" soon!;(