Fig. 1

Latent structure models of the 4DSQ scales. The depression model is strictly unidimensional. The other scales demonstrate bifactor structures. Boxes represent items and circles latent factors. The general factors are represented by “dis”, “dep”, “anx”, and “som”. The other factors represent group factors: “sleep” = disturbed sleep, “cope” = failure to cope, “upset” = symptoms related to past upsetting events, “ff-anx” = free floating anxiety, “musc” = musculoskeletal symptoms, “g-int” = gastro-intestinal symptoms, “c-vas” = cardiovascular symptoms. Coefficients are standardized factor loadings