Postdoctoral Fellow University of Washington School of Medicine Seattle, Washington
Loneliness is becoming increasingly recognized as a problem of clinical and public health significance (Badcock et al., 2023). Although this increase is concerning on its own, given the importance of social relationships and relational well-being to the human experience, loneliness is also associated with a host of mental and physical health problems, including depression. Despite decades of research establishing an association between loneliness and depression (Erzen & Çikrikci, 2018), however, little is known about how loneliness might increase the risk for depression and thus what appropriate intervention targets might be.
Integrating Cacioppo and colleagues’ (2006; 2018) evolutionary theory of loneliness with Reis and Shaver's (1988) interpersonal process model of the development of close and trusting relationships, we attempt to begin answering these questions. A racially diverse sample of 102 adults with elevated depression symptoms (≥ 10 on the PHQ-9) was recruited to participate in a 14-day experience sampling study. Participants responded to questions about momentary depressed mood, loneliness, and their social interactions 5 times a day in a random-interval design.
An anchor test planned missing design (Silvia et al., 2014) was used to decrease participant burden, and Bayesian mixed effects location scale models were used to answer our research questions. Results suggest that loneliness is associated with depressed mood at both the between- and within-person levels of analysis and predicts increases in depressed mood 3 and 6 hours later. We did not find evidence that engagement in social interaction or the quality of one's social interactions following experiences of loneliness moderated this association, nor was there evidence that variation in loneliness predicted depressed mood. Implications of these findings with respect to theory and clinical practice are discussed.
