Responses to depressive symptom items exhibit a common mathematical pattern across the European populations.

The theoretical distribution of responses to depressive symptom items in a general population remains unknown. Recent studies have shown that responses to depressive symptom items follow the same pattern in the US and Japanese populations, but the degree to which these findings can be generalized to other countries is unknown. The purpose of this study was to conduct a pattern analysis on the EU population's responses to depressive symptom items using data from the Eurobarometer. The Eurobarometer questionnaires include six depressive symptom items from the 12-item General Health Questionnaire. The pattern analysis revealed that, across the entire EU population, the ratios between "score = 2" and "score = 1" and between "score = 3" to "score = 2" were similar among the six items and resulted in a common pattern. This common pattern was characterized by an intersection at a single point between "score = 0" and "score = 1" and a parallel pattern between "score = 1" and "score = 3" on a logarithmic scale. Country-by-country analyses revealed that the item responses followed a common characteristic pattern across all 15 countries. Our results suggest that responses to depressive symptom items in a general population follow the same characteristic pattern regardless of the specific country.