Fig. 3From: Effect of COPD severity and comorbidities on the result of the PHQ-9 tool for the diagnosis of depression: results from the COSYCONET cohort studyEffect of comorbidities on the PHQ-9 sum scoreThe figure illustrates the dependence of the PHQ-9 score on the different comorbidities. Each single comorbidity was associated with an increase in the PHQ-9 sum score and these effects were additive.Back to article page