Reactivity to stressor pile-up in adulthood: effects on daily negative and positive affect.

This study used data from a 30-day diary study with 289 adults (age range 18-89 years) to model the effects of stressor pile-up on individuals' daily negative affect (NA) and positive affect (PA) and to test for age differences in these effects. Specifically, we developed a new approach to operationalize and model stressor pile-up and evaluated this approach using generalized mixed models, taking into account the gamma response distribution of the highly skewed daily NA data. Findings showed that pile-up of stressors over a 1-week period was significantly coupled with increases in individuals' daily NA above and beyond the effect of concurrent stressors. Findings also showed that the effects of stressor accumulation and concurrent stress were additive rather than multiplicative. Age interacted significantly with stressor accumulation so that a higher age was associated with less NA reactivity to stressor pile-up. Yet, we did not find such an age-related association for NA reactivity to concurrent daily stressors. Daily PA was not associated with daily stress or with stressor pile-up. The operational definition of stressor pile-up presented in this study contributes to the literature by providing a new approach to model the dynamic effects of stress, and by providing new ways of separating the effects of acute stressors from the effects of stressor pile-up. The age differences found in the present study suggest that older adults develop effective emotion regulation skills for handling stressor pile-up, but that they react to acute daily stressors in a similar way than younger adults.