The prevalence of depression based on the Patient Health Questionnaire-8 (PHQ-8) may vary depending on the scoring method.

1) To describe the prevalence of depression in Europe using two PHQ-8 scoring methods. 2) To identify the countries with the highest prevalence according to each method.

Data from 27 countries included in the European Health Survey (EHIS-2) for the year 2014/2015 were used (n=258,888). All participants who completed the PHQ-8 were included. The prevalence of depression and its 95% Confidence Interval (95%CI) were calculated overall for the whole of Europe and for each country using a PHQ-8≥10 cut-off point and the PHQ-8 algorithm scoring method. Weights derived from the complex sample design were considered for their calculation.

The overall prevalence of depression for all Europe was lower using the PHQ-8>=10 cut-off point (6.38%, 95%CI 6.24-6.52) than the PHQ-8 algorithm (7.01%, 95%CI, 6.86-7.16). Using the PHQ-8≥10 cut-off point, the highest prevalence was observed in Iceland (10.33%, 95%CI, 9.33-11.32), Luxembourg (9.74%, 95%CI, 8.76-10.72) and Germany (9.24%, 95%CI, 8.82-9.66). Using the PHQ-8 algorithm the highest rates were observed in Hungary (10.99%, 95%CI,10.14-11.84), Portugal (10.63%, 95%CI, 9.96-11.29) and Iceland (9.80%, 95%CI, 8.77-10.83).

There is variability in the prevalence of depression rates in Europe according to the PHQ-8 scoring method. These findings suggest the necessity of identify the method of choice for each country comparing with a gold standard measure (clinical diagnosis). Countries with consistent higher prevalence of depression based on PHQ-8 regardless of scoring method deserve further study.

This work has been funded by CIBERESP (ESP21PI05)

Item 9 of the Patient Health Questionnaire-9 (PHQ-9) queries about thoughts of death and self-harm, but not suicidality. Although it is sometimes used to assess suicide risk, most positive responses are not associated with suicidality. The PHQ-8, which omits Item 9, is thus increasingly used in research. We assessed equivalency of total score correlations and the diagnostic accuracy to detect major depression of the PHQ-8 and PHQ-9.

We conducted an individual patient data meta-analysis. We fit bivariate random-effects models to assess diagnostic accuracy.

16 742 participants (2097 major depression cases) from 54 studies were included. The correlation between PHQ-8 and PHQ-9 scores was 0.996 (95% confidence interval 0.996 to 0.996). The standard cutoff score of 10 for the PHQ-9 maximized sensitivity + specificity for the PHQ-8 among studies that used a semi-structured diagnostic interview reference standard (N = 27). At cutoff 10, the PHQ-8 was less sensitive by 0.02 (−0.06 to 0.00) and more specific by 0.01 (0.00 to 0.01) among those studies (N = 27), with similar results for studies that used other types of interviews (N = 27). For all 54 primary studies combined, across all cutoffs, the PHQ-8 was less sensitive than the PHQ-9 by 0.00 to 0.05 (0.03 at cutoff 10), and specificity was within 0.01 for all cutoffs (0.00 to 0.01).

PHQ-8 and PHQ-9 total scores were similar. Sensitivity may be minimally reduced with the PHQ-8, but specificity is similar.