July 17, 2025
Dear Colleagues,
The National Social Anxiety Center (NSAC) provides information about relevant and current research in service of disseminating and promoting evidence-based treatment. This month’s summary is written by Suma Chand, Ph.D. of NSAC St. Louis. The article, Loneliness Mediates the Association between Trait Social Anxiety and Cardiovascular Reactivity to Acute Psychological Stress by O’Riordan and Costello (2025) investigates the role of loneliness in mediating the relationship between social anxiety and cardiovascular reactivity to acute psychological stress.
Previous studies have shown that social anxiety is associated with several health problems, including heart issues, inflammation, and high blood pressure. Studies have explored how socially anxious individuals respond to acute stress, the kind of short-term aggravations that we face on a day-to-day basis. The results reported have, however, been inconsistent. In this study, the authors have explored another factor, namely loneliness, to explain the inconsistent results and to understand the connection between social anxiety and cardiovascular reactivity in the face of acute psychological stress.
Over two days, 658 adult subjects:
- Completed questionnaires assessing social anxiety and loneliness.
- Underwent a cardiovascular reactivity protocol involving baseline rest and two stress-inducing tasks (a mental arithmetic task and a Stroop color-word task).
- They had their blood pressure and heart rate continuously monitored.
- Self-reported stress levels were assessed before and after tasks.
Key Findings:
- Social Anxiety and Self-Reported Stress: Individuals with higher social anxiety reported feeling more stressed during the tasks.
- Social Anxiety and Cardiovascular Reactivity: Although social anxiety was associated with increased self-reported stress, no significant associations between social anxiety and measures of cardiovascular reactivity were observed in regression analyses. This indicates that social anxiety alone did not directly predict how much participants’ blood pressure or heart rate changed during the stressful tasks.
- Loneliness and Cardiovascular Reactivity: Loneliness was significantly associated with lower systolic and diastolic blood pressure reactivity, suggesting a blunted physiological response to stress.
- Mediating Role of Loneliness: Mediation analysis showed that social anxiety mediated the association between trait social anxiety and both systolic blood pressure (SBP) reactivity and diastolic blood pressure (DBP) reactivity. This is indicative of social anxiety being linked to increased loneliness, which in turn contributed to diminished blood pressure responses.
Implications:
While blunted cardiovascular responses may seem like a positive outcome, recent research has challenged this traditional view. A blunted cardiovascular response to stress has been found to be linked to various negative health outcomes, including adverse cardiovascular events. This article highlights the key role that loneliness plays in social anxiety and contributes to adverse physiological responses to acute stress and, potentially, to ultimately, poorer long-term health risks.
Limitations:
The authors have acknowledged limitations of the study. They include:
- The design cannot definitively establish whether social anxiety leads to loneliness, which then affects cardiovascular reactivity. The relationships may be more complex or bidirectional.
- It’s unclear whether these effects remain stable over time or fluctuate based on life circumstances.
- The study used a general population rather than a clinical sample, meaning the findings may not fully apply to individuals with diagnosed social anxiety disorder. Effects could be more pronounced in clinical populations.
These points suggest avenues for further research, particularly in clinical settings and longitudinal studies.
Question for Clinicians: How often do your clients with Social Anxiety Disorder mention loneliness as a problem they would like to address in therapy? If they do, then do you address it separately or address it as being linked to social anxiety and stay focused on addressing the social anxiety disorder?
O’Riordan, A., & Costello, A. M. (2025). Loneliness mediates the association between trait social anxiety and cardiovascular reactivity to acute psychological stress. International Journal of Psychophysiology, 209, 112517.
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Suma Chand, PhD, A-CBT
Representing NSAC St. Louis
(The Cognitive Behavior Therapy Program of SLUCare)