Table 4. Receiver operating characteristic curves of the PHQ-9 scores in relation to HDRS categories: Mild, moderate, severe.

Depression severity	Optimal cut-off	Sensitivity	Specificity	PPV	NPV	AUC
Mild (HDRS >7)	>4	72.4	69.6	79.1	61.2	0.80 (0.74;0.86)
Moderate (HDRS >16)	>4	88.8	59.1	50.6	91.8	0.84 (0.80;0.90)
Severe (HDRS >23)	>6	93.7	65.3	32.4	98.3	0.87 (0.83;0.93)
Rwandan version (HDRS > 17)	>6	84.1	75.1	58.2	92.0	0.86 (0.82;0.90)