Table 4 Validity of different combinations of items in the Primary care Screening Questionnaire for Depression (PSQ4D)
Cut-off score in PSQ4DSensitivitySpecificityPositive predictive valueNegative predictive valueAccuracy (correctly classified)
Any two questions positive (n=294)0.960.870.740.980.90
Any three questions positive (n=192)0.760.970.890.950.91
Q1Q2 positive (n=168)0.660.970.890.890.89
Q1Q3 positive (n=200)0.740.950.840.910.89
Q1Q4 positive (n=160)0.550.980.920.850.87
Q2Q4 positive (n=135)0.660.960.850.880.87
Q3Q4 positive (n=175)0.630.980.910.880.88
Q1Q2Q3 positive (n=155)0.630.970.910.880.88
Q1Q2Q4 positive (n=155)0.520.990.940.850.86
Q2Q3Q4 positive (n=126)0.500.990.970.840.86
All questions positive (n=116)0.550.980.920.850.87
  • PSQ4D, Primary care Screening Questionnaire for Depression; Q1, question on depressed mood; Q2, question on lack of interest; Q3, question on reduced energy; Q4, question on lack of sleep.