The effect of social interaction quantity and quality on depressed mood and loneliness: A daily diary study

Background Concerns about the possible effects of social distancing during the COVID-19 pandemic highlighted several gaps in our knowledge about the association between social interactions and mental health. The current study aimed to characterize the unique effect of social interaction quantity and quality on daily depressed mood and loneliness and to identify the degree to which these processes operate at the within-person and between-person levels of analysis. Methods A community sample of 515 adults was recruited to participate in 75 days of daily surveys. Participants reported on daily feelings of loneliness, depressed mood, social interaction frequency, engagement in vulnerable self-disclosure, and perceived responsiveness. Linear mixed models were used to identify the effect of daily social interaction quantity and quality on loneliness and depressed mood and to characterize the degree to which these effects varied across individuals. Results Social interaction quantity and perceived responsiveness were negatively associated with depressed mood and loneliness at the within-person level of analysis. Perceived responsiveness was also negatively associated with depressed mood and loneliness at both the within-person and between-person levels of analysis. Random slopes analysis revealed substantial heterogeneity in the within-person effects. Limitations The non-experimental design of this study precludes drawing causal conclusions. Furthermore, demographic and/or geographic differences in the observed effects may limit generalization. Conclusions Engaging in more frequent, high-quality interactions may protect against daily depressed mood and loneliness despite one's average level of these variables. Future research is needed to establish causality and identify the degree to which these findings generalize across samples and time.