Additive, Curvilinear, and Interactive Relations of Anxiety and Depression With Indicators of Psychosocial Functioning.

This study examines additive, curvilinear, and interactive relations of anxiety and depression with several subjective indicators of intrapersonal (i.e., hope, self-compassion, shame) and interpersonal (i.e., social connectedness, quality of social relationships) functioning in a sample of adults (=547,  = 43.37 ± 12.02, female = 56.88%) seeking treatment for psychological difficulties. Results of complementary analyses were largely consistent with the hypothesis that increasing levels of anxiety and depression would correspond with worse psychosocial functioning, although nonlinear relations indicated that the effect of depression progressively attenuated at higher levels of symptom severity. Whereas the findings generally supported additive effects of anxiety and depression, the hypothesis that there would be synergistic effects of anxiety and depression was not supported. Supplementary group comparisons revealed that the functional implications of subsyndromal combinations of anxiety and depression may be comparable to those associated with symptoms that meet more traditional standards (i.e., syndromal or dimensional definitions) of comorbid anxiety-depression. The findings offer further insight into the complex relations of anxiety and depression with psychosocial functioning and emphasize the importance of detecting and offering appropriate treatments for anxiety and depression symptoms that coexist at subsyndromal levels.