Better together? Polyregulation across interpersonal and intrapersonal strategies in civilian and veteran daily life.

Emotion regulation research has traditionally examined intrapersonal and interpersonal strategies in isolation, limiting understanding of their combined effectiveness in daily life. This study used ecological momentary assessment (EMA) to compare the effectiveness of combined interpersonal-intrapersonal strategies versus intrapersonal-only approaches across two samples. Study 1 analysed 10,739 observations from 156 civilians over 21 days, finding that combined strategies were modestly more effective for decreasing negative emotions but did not differ significantly from intrapersonal-only strategies for enhancing positive emotions or problem-solving facilitation. Study 2 analysed 3,894 observations from 70 veterans, revealing significantly larger combined strategy advantages for both decreasing negative emotions and enhancing positive emotions, with effect sizes approximately 2-4 times larger than civilians. Problem-solving effectiveness was unrelated to strategy type in either sample, instead being driven by the number of strategies deployed. Multilevel models revealed substantial individual variability in combined strategy benefits across both samples. These findings provide naturalistic evidence that integrating interpersonal and intrapersonal emotion regulation strategies may enhance emotional outcomes, while highlighting important population differences that have implications for personalised clinical interventions.