Fig. 1. Relationship between somatic symptom severity as measured by the PHQ-15 and decline in functional status as measured by the six subscales of the SF-20. The decrement in SF-20 scores are shown as the difference between each PHQ-15 severity group and the reference group (ie, those with PHQ-15 scores of 0–4). SF-20 scores are adjusted for age, sex, education, and number of physical disorders. Effect size is the difference in adjusted means divided by the pooled standard deviation for that scale.