Objectives:
Studies have shown age differences in adapting to the COVID-19 pandemic. However, the processes explaining these age differences remain unclear. Intra- and interpersonal emotion regulation – such as ruminative brooding and co-brooding - play an important role in psycho-social adjustment and develop across the life-span. This study aims at investigating COVID-19-related adjustment disorder symptoms in relation to age and whether this relation can be explained by age-differences in rumination in a multi-national sample. As a second research goal, linguistic indicators of ruminative processing when writing about the pandemic will be examined with reference to age.

Methods:
N = 1401 participants (from USA, UK, Switzerland, and Germany, aged 18-88) filled out an online survey and completed a writing task. Measures include brooding, co-brooding, adjustment disorder symptoms, and language indicators of negative self-focus and communal focus while writing down thoughts and feelings regarding the pandemic.

Findings:
Older participants reported less adjustment disorder symptoms which was mediated by less (co-)brooding. Participants who reported more (co-)brooding wrote about COVID-19 more negatively. While in younger adults (age 18-40) more self-focus was associated with higher ruminative brooding, in older adults (age 59-88) it was associated with less maladaptive emotion regulation.

Discussion:
These findings contribute to a better understanding of regulatory mechanisms that help explain age differences in mental health. They warrant further research considering age-related differences, as our results suggest not only more adaptive emotion regulation as a resilience factor in older individuals, but also different qualities of self-focus while processing stressful events across the lifespan.