2026 ECNP Congress

PS03-3124

Screening for postpartum depression in Latvia: validation and optimal cut-offs of the PHQ-9 against a structured diagnostic interview

Marija Lazareva — L. Renemane, S. Cipare, V.V. Vinogradova, L. Rubene-Kesele, L. Kise, E. Rancans · Rīga Stradiņš University, Department of Psychiatry and Narcology, Riga, Latvia

2026 ECNP Congress

Introduction

Postpartum depression (PPD) is a common and clinically significant condition associated with adverse maternal, infant, and family outcomes [1], [2]. Early identification through reliable screening instruments remains a priority in routine outpatient obstetric and psychiatric care. While the Patient Health Questionnaire-9 (PHQ-9) is widely used to identify postpartum depressive symptoms in both clinical and research settings, its diagnostic performance has not yet been validated in postpartum populations in Latvia. Given that optimal screening cut-off values may vary across countries due to cultural, linguistic, and healthcare context differences, local validation against structured diagnostic interviews is necessary to ensure accurate detection and effective implementation of screening in maternal healthcare services and improve timely access to treatment [3], [4].

Aims

This study aimed to evaluate the diagnostic performance of the PHQ-9 for identifying PPD in an outpatient population of women in Latvia and to determine optimal screening cut-off values using a structured diagnostic interview as the reference standard.

Methods

This cross-sectional validation study was conducted at the outpatient department of Riga Maternity Hospital, the largest maternity outpatient care facility in Latvia. All consecutive women aged ≥18 years attending routine follow-up visits 4-6 weeks after childbirth over a 12-months period were screened using the PHQ-9. Women scoring ≥5 were invited to participate in a second-stage assessment within two weeks of initial screening, using the Mini International Neuropsychiatric Interview (MINI 7.0.2), which was used to confirm the diagnosis of PPD. Diagnostic performance of the PHQ-9 was evaluated using receiver operating characteristic (ROC) analysis. Sensitivity, specificity, predictive values, likelihood ratios, and the Youden index were calculated across multiple thresholds to determine optimal cut-off scores. Internal consistency was assessed using Cronbach’s alpha.

Results

A total of 272 postpartum women aged 18-49 years were screened using the PHQ-9, of whom 117 (43.0%) were screen-positive (PHQ-9 ≥5). Diagnostic validation against the MINI interview was completed in 92 participants. The PHQ-9 demonstrated acceptable internal consistency (Cronbach’s α=0.788). ROC analysis indicated good diagnostic accuracy of the PHQ-9 for identifying MINI-confirmed PPD, with the area under the curve (AUC) of 0.846 (SE=0.049, 95% CI 0.750-0.942, p<0.001). The cut-off score of ≥7 provided the most clinically appropriate screening performance, with sensitivity of 0.84, specificity of 0.67, and Youden index of 0.51, indicating an optimal balance between case detection and false-positive rates. A higher threshold of ≥10 showed the same Youden index (0.51) but greater specificity (0.93) and may be considered for diagnostic use.

Conclusions: The PHQ-9 demonstrated acceptable internal consistency and good diagnostic accuracy as a screening instrument for PPD in an outpatient population in Latvia. A cut-off score of ≥7 appears optimal for routine postpartum screening, as it maximises sensitivity and supports early identification of women at risk. These findings support the integration of PHQ-9-based screening into structured postpartum outpatient care pathways in Latvia and highlight the importance of population-specific validation to ensure accurate and context-appropriate screening strategies.

References

  1. Slomian, J., Honvo, G., Emonts, P., Reginster, J. Y., & Bruyère, O. (2019). Consequences of maternal postpartum depression: A systematic review of maternal and infant outcomes. In Women’s Health (Vol. 15). https://doi.org/10.1177/1745506519844044.
  2. Ö. Palancı AY and S. Aktaş, “The effect of maternal functional and postpartum depression status on breastfeeding self-efficacy of the mothers: A cross-sectional study,” Health Care Women Int, vol. 45, no. 2, pp. 236–250, 2024, doi: 10.1080/07399332.2021.1973008.
  3. Wang, L.; Kroenke, K.; Stump, T.E.; Monahan, P.O. Screening for perinatal depression with the Patient Health Questionnaire depression scale (PHQ-9): A systematic review and meta-analysis. Gen. Hosp. Psychiatry 2020, 68, 74–82.
  4. Matthey, S. Is Validating the Cutoff Score on Perinatal Mental Health Mood Screening Instruments, for Women and Men from Different Cultures or Languages, Really Necessary? Int. J. Environ. Res. Public Health 2022, 19, 4011.