Loneliness Partially Mediates Link Between Anxiety, Depression, and Suicidal Ideation
Key Clinical Summary
- In a cross-sectional analysis of 62,685 US adults, loneliness partially mediated the association between anxiety, depressive symptoms, and suicidal ideation.
- Depressive symptoms (r = 0.39; P < .001), anxiety symptoms (r = 0.33; P < .001), and loneliness (r = 0.31; P < .001) were each independently associated with suicidal ideation.
- Loneliness accounted for 25% of the association between anxiety and suicidal ideation and 10% of the association between depressive symptoms and suicidal ideation.
Loneliness significantly contributes to the relationship between anxiety symptoms, depressive symptoms, and suicidal ideation among US adults, according to analysis findings published in JAMA Network Open. Using data from the National Institutes of Health’s All of Us Research Program, investigators found that loneliness partially mediated these associations, suggesting it may represent a transdiagnostic intervention target.
Study Findings
The cross-sectional study analyzed survey data collected between May 31, 2017, and October 1, 2023, from 62,685 adults who completed the mental health component of the All of Us Research Program. The mean (SD) participant age was 61.8 (16.1) years and 65% were women.
Anxiety symptoms were assessed using the 7-item Generalized Anxiety Disorder scale (GAD-7), depressive symptoms using the first 8 items of the 9-item Patient Health Questionnaire (PHQ-9), loneliness using the UCLA Loneliness Scale, and suicidal ideation using item 9 of the PHQ-9.
Anxiety symptoms (r = 0.33; P < .001), depressive symptoms (r = 0.39; P < .001), and loneliness (r = 0.31; P < .001) were all significantly correlated with suicidal ideation. After controlling for gender and race and ethnicity, depressive symptoms (B = 0.017; 95% CI, 0.017–0.019), anxiety symptoms (B = 0.004; 95% CI, 0.004–0.006), and loneliness (B = 0.007; 95% CI, 0.007–0.008) each accounted for significant variability in suicidal ideation.
Mediation analyses demonstrated that loneliness partially mediated the association between anxiety symptoms and suicidal ideation (average causal mediation effect = 0.01; proportion mediated = 0.25; total association = 0.03; P < .001). A similar pattern was observed for depressive symptoms (average causal mediation effect = 0.003; proportion mediated = 0.10; total association = 0.02; P < .001).
Clinical Implications
These findings underscore loneliness as a clinically relevant factor in suicide risk assessment. While anxiety and depressive symptoms remain central drivers of suicidal ideation, the data suggest that a meaningful proportion of their association with suicidal thoughts operates through perceived social disconnection.
For clinicians, this highlights the importance of assessing loneliness alongside standard measures of mood and anxiety. Because loneliness partially mediated 25% of the anxiety–suicidal ideation link and 10% of the depressive symptom–suicidal ideation link, interventions targeting social isolation may help interrupt progression to suicidal ideation.
Expert Commentary
“Although anxiety and depressive symptoms were associated with suicidal ideation, much of these associations appeared to be mediated by loneliness,” wrote Katherine Musacchio Schafer, PhD, Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, and study coauthors. “This finding highlights loneliness as a potential transdiagnostic treatment target that could be focused on via scalable interventions to reduce the incidence and intensity of suicidal ideation,” they concluded.
