Is depression comparable between asylum seekers and native Germans? An investigation of measurement invariance of the PHQ-9.

BACKGROUND

Asylum seekers show high prevalence of depressive disorders compared to native populations. For the assessment of depression, the Patient Health Questionnaire-9 (PHQ-9) is a widely used instrument that has shown high validity and reliability. However, it is largely unknown whether PHQ-9 scores are comparable between asylum seekers living in Western countries and native populations, and whether results can be interpreted without reservation.

METHOD

Data from asylum seekers living in Germany (n = 243) and Germans without a migration background (n = 171) were used to analyze measurement invariance of the PHQ-9. Configural, scalar, and metric invariance was investigated, and test functioning was determined.

RESULTS

The PHQ-9 was not measurement invariant across Germans without a migration background and asylum seekers living in Germany. Differences were found regarding metric invariance and scalar invariance. The items anhedonia, depressed mood, appetite changes, psychomotor changes, and suicidal ideation had lower loadings and lower thresholds in asylum seekers compared to Germans without a migration background. That led to an overestimation translated into approximately one point on the sum-score.

LIMITATIONS

The study limitations include a heterogeneous sample of asylum seekers regarding countries of origin, and the utilization of the different language versions of the PHQ-9.

CONCLUSION

Our results may have implications for studies comparing levels of depression between asylum seekers and native Western samples. Even with the same latent level of depression, asylum seekers may have higher scores on several items and consequently a higher sum score. Therefore, the present results suggest a new determination or differentiation of the cut-off scores that were derived from Western samples.