Fig. 1

Initial (theoretical) model of depression in ankylosing spondylitis. This model was the initial, hypothesized model of depression in AS, based on biological plausibility and existing evidence. Standardized regression coefficients are presented in Table 2. The numbered HADS items represent the individual corresponding items on the HADS questionnaire. BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; HADS, Hospital Anxiety and Depression Scale; SCQ, Self-Administered Comorbidity Questionnaire; SRPQ, Social Role Participation Questionnaire