Within-person changes in emotional complexity are associated with concurrent changes in mental health symptoms.

Several constructs reflect features of everyday emotional experience that have been theorized to support mental well-being at the between-person level. These include emotional granularity (the ability to identify and label emotions precisely), emotion covariation (the ability to experience positive and negative emotions simultaneously), and emodiversity (the ability to experience a variety and relative abundance of emotions over time). Emerging evidence suggests that these qualities of everyday emotional experience may reflect abilities or skills that could be modified over time. This study examines whether repeated emotion reporting through experience sampling is associated with changes in these features of emotional complexity over time and whether any such changes co-occur with corresponding changes in mental health symptoms. Participants (N = 123) from the general public reported their current emotions multiple times a day for 6 weeks alongside biweekly assessments of self-reported alexithymia and depression, anxiety, and somatic symptom severity. Data were collected between 2022-2023. We found that participants' emotional granularity and emotion covariation significantly increased while their emodiversity decreased over time. Moreover, increases in emotional granularity corresponded with concurrent decreases in alexithymia and depression symptoms while decreases in negative emodiversity corresponded with lesser alexithymia and anxiety and depression symptoms. Findings support past demonstrations that experience sampling of emotional experience itself can serve as an intervention to promote changes in emotional granularity, emotion covariation, and emodiversity. The findings also offer initial evidence that changes in these constructs over time are associated with concurrent within-person fluctuations in mental health symptoms.