Sine Off On It: Sinusoidal waves as models of shame and stress in social anxiety.

The experiences of shame and stress are associated with social anxiety disorder (SAD). In the present study, we examined a sample of 111 participants (54 with SAD and 57 without SAD) who completed a daily diary measuring stress and shame over the course of 21 days. We modelled the temporal changes in shame and stress using linear and quadratic models as well as sinusoidal models. We found sinusoidal models to be superior to linear and quadratic ones in capturing the temporal dynamics of stress and shame. Specifically, linear models explained 9.91 % and 11.69 % of the changes in shame and stress over time (respectively), whereas sinusoidal models explained 35.76 % and 39.10 % of the changes in shame and stress over time (respectively). The differences in explained variances were statistically significant for both shame and stress. In addition, we examined whether the parameters of the best-fitting sinusoidal models were associated with levels of social anxiety. As expected, we found that the vertical offset parameters (i.e., average levels) of both shame and stress were significantly and positively associated with social anxiety. In addition, we found that fluctuations (sine wave amplitudes) in shame were positively associated with social anxiety whereas fluctuations in stress were negatively associated with social anxiety. Our findings demonstrate that sinusoidal waves can model temporal changes in emotions successfully. Moreover, sine wave parameters of shame and stress can be markers of social anxiety and can have implications for diagnosis and treatment.