Four-Question PHQ-4 Screen Validated in Returned Cambodian Migrant Workers

A four-item questionnaire appears to reliably flag anxiety and depression among returned migrant workers in Cambodia, according to a cross-sectional validation study published in Discover Psychology. The Patient Health Questionnaire-4, or PHQ-4, is a widely used ultra-brief instrument for assessing anxiety and depression, but its psychometric properties had not previously been validated among returned migrant workers in Cambodia.

The research team recruited 392 returned Cambodian migrant workers across four provinces with high rates of labor migration in October 2022. Participants had a mean age of 34.7 years, with 52 percent men and 48 percent women. The mean overall PHQ-4 score was 2.13 (standard deviation 2.24), indicating that most respondents reported none to mild psychological distress.

Reliability was assessed using Cronbach’s alpha, and the PHQ-4 achieved an alpha of 0.78, a value within the range conventionally described as acceptable internal consistency.

The structural question of whether the PHQ-4 measures one general distress dimension or two distinct ones was addressed with confirmatory factor analysis. The single-factor model fit the data poorly, with a comparative fit index of 0.97 but a Tucker-Lewis index of 0.78 and a root mean square error of approximation of 0.23. The two-factor model, by contrast, showed excellent fit: a CFI of 0.99, TLI of 0.98, RMSEA of 0.035 and a standardized root mean square residual of 0.016. The two latent factors, representing anxiety and depression, were strongly correlated at r = 0.79 (p < 0.001).

Beyond internal structure, the researchers tested construct validity by examining whether PHQ-4 scores associated with occupational health risk factors, using multivariable logistic regression. Higher scores were significantly linked to long working hours, with an adjusted odds ratio of 1.45 (95 percent confidence interval 1.10 to 1.92); to unsafe working conditions, with an adjusted odds ratio of 1.63 (95 percent confidence interval 1.21 to 2.20); and to hazardous work exposure, with an adjusted odds ratio of 1.38 (95 percent confidence interval 1.05 to 1.82). These associations do not establish that occupational hazards cause psychological distress, but they show that the instrument behaves as expected in this population, a pattern the authors describe as exposure-based construct validity.

The findings carry practical weight for low- and middle-income countries, where large-scale surveys and resource-constrained settings increasingly require ultra-brief screening tools. An ultra-brief screen that non-specialized personnel can administer quickly could support workplace surveillance, returnee health checks, primary care, and community outreach by nongovernmental organizations in Cambodia, the authors conclude.

Several caveats temper the conclusions. The study was cross-sectional, capturing a single point in time, and its sample was drawn from four high-migration provinces, so generalization to other regions or to migrants still abroad remains untested. Symptom levels in the sample were predominantly low, which means performance in high-distress or clinical populations would need separate evaluation.

Even with those limits, the study addresses a documented gap for a widely used international instrument. The evidence now on record supports the PHQ-4 as a reliable and valid ultra-brief screen among returned Cambodian migrant workers, and the authors point to its low-burden, scalable format for rapid mental health screening in resource-limited settings.

Subject of Research: Psychometric validation of the PHQ-4 anxiety and depression screening tool among returned Cambodian migrant workers

Article Title: Psychometric validation of the patient health questionnaire 4 items for screening anxiety and depression among returned Cambodian migrant workers

Article References: Chien, S., Liu, K.-L., Khov, H., & Chan, C.-C. (2026). Psychometric validation of the patient health questionnaire 4 items for screening anxiety and depression among returned Cambodian migrant workers. Discover Psychology. https://doi.org/10.1007/s44202-026-00945-8

Image Credits: AI Generated

DOI: 10.1007/s44202-026-00945-8

Keywords: PHQ-4, mental health screening, Cambodia, migrant workers, anxiety, depression, psychometrics, confirmatory factor analysis, occupational health, validation, cross-sectional study, Psychometric