Validation of the Edinburgh Postnatal Depression Scale (EPDS) as a screening tool for postnatal depression in Samoan and Tongan women living in New Zealand.

Objective: To validate the EPDS as a screening tool for postnatal depression in Samoan and Tongan women living in New Zealand.

Methods: 85 Samoan and 85 Tongan women who delivered babies at Middlemore Hospital from February 2009 to June 2010 completed the EPDS questionnaire and from 4 weeks after delivery followed by an interview using a Composite International Diagnostic Interview (CIDI) within 4 weeks of the EPDS completion.

Results: The EPDS in English, Tongan and Samoan languages is a valid and consistent tool for screening for PND in Samoan and Tongan women. A cut-off score of ≥10 for Tongan and ≥11 for Samoan women gave the best sensitivity (80%) and specificity (80%) combination whereas a higher cut-off of ≥16 for Tongan and ≥17 Samoan women gave the best positive predictive value (82%) and negative predictive value (86%) for serious depression. The lower cut-off scores correctly diagnosed 82% and the higher cut-offs more than 87% of women with serious depression.

Conclusions: The EPDS was an acceptable and valid tool for PND screening in English, Samoan and Tongan languages amongst Samoan and Tongan women. The cut-offs for PND screening were dissimilar in the two groups with a ≥10 for Tongan and ≥11 for Samoan women. A higher cut-off of ≥16 for Tongan and ≥17 for Samoan women improves the predictive value of the instrument.