There is a variety of rating scales for symptoms of depression, and the Clinically Useful Depression Outcome Scale (CUDOS) is one of them. One of the advantages of CUDOS over the well known Beck depression inventory (BDI) is that this one can be used freely for research purposes.

The CUDOS can be used to indicate cases of depression. The authors write:

Our data and clinical experience allowed us to approximate ranges of scores corresponding to a dimensional assessment of depression severity. We recommend that the nondepressed range corresponds to CUDOS scores of 0 to10; minimal depression, 11 to 20; mild depression, 21 to 30; moderate depression, 31 to 45; and severe depression, 46 and above.

— Zimmerman et al. (2008)
See also the Personal Health Questionniare (to measure depression) in the PsyToolkit survey library.

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CUDOS can be used freely, but as with any scale you use, you always need to acknowledge the creators.

The survey code for PsyToolkit

Copy and paste this code to your PsyToolkit account if you want to use the scale in your own online research project
scale: howtrue
- {score=0} not at all true (0 days)
- {score=1} rarely true (1-2 days)
- {score=2} sometimes true (3-4 days)
- {score=3} often true (5-6 days)
- {score=4} almost always true (every day)

l: CUDOS_1_16
t: scale howtrue
o: random
q: During the past week, including today...
- I felt sad or depressed
- I was not as interested in my usual activities
- My appetite was poor and I didn't feel like eating
- My appetite was much greater than usual
- I had difficulty sleeping
- I was sleeping too much
- I felt very fidgety, making it difficult to sit still
- I felt physically slowed down, like my body was stuck in mud
- My energy level was low
- I felt guilty
- I thought I was a failure
- I had problems concentrating
- I had more difficulties making decisions than usual
- I wished I was dead
- I thought about killing myself
- I thought that the future looked hopeless

l: CUDOS_17
t: radio
q: Overall, how much have symptoms of depression interfered with or
 caused difficulties in your life during the past week?
- {score=0} not at all
- {score=1} a little bit
- {score=2} a moderate amount
- {score=3} quite a bit
- {score=4} extremely

l: CUDOS_18
t: radio
q: How would you rate your overall quality of life during the past week?
- {score=0} very good, my life could hardly be better
- {score=1} pretty good, most things are going well
- {score=2} the good and bad parts are about equal
- {score=3} pretty bad, most things are going poorly
- {score=4} very bad, my life could hardly be worse

l: score
t: set
- sum $CUDOS_*

l: depressed
t: info
q: Your score is {$score} on the Clinically Useful Depression Outcome Scale (CUDOS):<br>
You can use the table below to interprete this score.<br>
<li>0-10 = non-depressed
<li>11-20 = minimal depression
<li>21-30 = mild depression
<li>31-45 = moderate depression
<li>46-72 = severe depression
If you are concerned about your mental health, make sure you seek help,<br>
for example from your doctor.<br>
If you are a student, you can contact your student services or mentor.<br>
Almost all schools and universities have a place where you can ask for help.<br>


  • Zimmerman, M., Chelminski, I, McGlinchey, J. B. and Posternak, M. A. (2008). A clinically useful depression outcome scale. Comprehensive Psychiatry, 49, 131-140.