Fig. 3From: Distributional patterns of item responses and total scores on the PHQ-9 in the general population: data from the National Health and Nutrition Examination SurveyTotal score distribution of the PHQ-9. a The total score distribution was right-skewed, and the frequency of the zero score was 31.9%. b Using the log-normal scale, the total score distribution showed a linear pattern. As indicated by the arrow, the total score distribution exhibited slightly higher frequencies compared to those predicted from the exponential pattern at the lower end of the distributionsBack to article page