Depression - 2 questions can rule out the diagnosis
Clinical Bottom Line
Negative responses to the 2-question case-finding instrument can rule out depression.
Whooley MA, Avins, AL, Miranda J, Browner WS. Case-finding instruments for depression: Two questions are as good as many. J Gen Intern Med 1997;12:439-45.
In patients with suspected depression what is the accuracy of a 2-question case-finding instrument for depression compared with 6 previously validated instruments?
"depression" or "depressive disorder" and "sensitivity and specificity" and "questionnaire" and "primary care" or "primary health care" in MEDLINE.
590 consecutive patients (mean age 53 years, 97% men) who visited an urgent-care clinic at a Veterans Affairs Hospital in the United States were given a self-report questionnaire that included the 2-question instrument taken from the Primary Care Evaluation of Mental Disorders Procedure: "During the past month, have you often been bothered by feeling down, depressed, or hopeless?" and " During the past month, have you often been bothered by little interest or pleasure in doing things?" The patients also completed 6 other validated instruments for detecting depression. The diagnostic standard was the National Institute of Mental Health Diagnostic Interview Schedule that was administered by trained psychology students who were blinded to the results of the case-finding instruments. Prevalence of depression in this sample was 18%, which is higher than other primary care settings.
a + b
c + d
a + c
b + d
Sensitivity = a/(a+c)
Sensitivity = 93/97
Sensitivity = 96%
Specificity = d/(b+d)
Specificity = 250/439
Specificity = 57%
Likelihood Ratio for a positive test result (LR+) = sens/(1-spec)
Likelihood Ratio for a positive test result (LR+) = 0.96/1-0.57
Likelihood Ratio for a positive test result (LR+) = 2.2
Likelihood Ratio for a negative test result (LR-) = (1-sens)/spec
Likelihood Ratio for a negative test result (LR-) = 1-0.96/0.57
Likelihood Ratio for a negative test result (LR-) = 0.07
Sample was not representative of most primary health care agencies (predominantly unemployed men with a high prevalence of depression). Would want to test the instrument on a more representative sample.
Donna Ciliska RN, PhD.
Associate Professor, School of Nursing
McMaster University, Hamilton, Ontario, Canada.
Fax: (905) 546-0401
Appraised February 1999.