How may I measure my depression?

The items below refer to how you have felt and behaved **during the past
week.** For each item, indicate the extent to which it is true, by
circling one of the numbers that follows it. Use the following scale:
0 = Not at all
1 = Just a little
2 = Somewhat
3 = Moderately
4 = Quite a lot
5 = Very much
1. I do things slowly..........0 1 2 3 4 5
2. My future seems hopeless.............0 1 2 3 4 5
3. It is hard for me to concentrate on reading.....0 1 2 3 4 5
4. The pleasure and joy has gone out of my life..0 1 2 3 4 5
5. I have difficulty making decisions.,0 1 2 3 4 5
6. I have lost interest in aspects of life that
used to be important to me.................0 1 2 3 4 5
7. I feel sad, blue, and unhappy..........0 1 2 3 4 5
8. I am agitated and keep moving around............0 1 2 3 4 5
9. I feel fatigued.................0 1 2 3 4 5
10. It takes great effort for me to do simple
things................0 1 2 3 4 5
11. I feel that I am a guilty person who
deserves to be punished....0 1 2 3 4 5
12. I feel like a failure.......0 1 2 3 4 5
13. I feel lifeless--more dead than alive...............0 1 2 3 4 5
14. My sleep has been disturbed:
too little, too much, or broken sleep...0 1 2 3 4 5
15. I spend time thinking about HOW I might
kill myself.........0 1 2 3 4 5
16. I feel trapped or caught.................0 1 2 3 4 5
17. I feel depressed even when good things
happen to me...0 1 2 3 4 5
18. Without trying to diet, I have lost,
or gained, weight...............0 1 2 3 4 5