The Role of Vulnerability and Responsiveness in Cardiovascular Disease Biomarkers Associated With Loneliness

Recent studies have found that loneliness has the same impact on morbidity and mortality as smoking cigarettes and twice that of obesity. One proposed pathway by which loneliness impacts morbidity and mortality is through cardiovascular disease. Loneliness is regularly associated with increased sympathetic nervous system and decreased parasympathetic nervous system engagement, both reliable biomarkers of increased risk of cardiovascular disease. One possible explanation for the this phenomena is that individuals who experience loneliness experience meaningful disruptions to the interpersonal process where they fail to disclose when appropriate or react to other individuals disclosure. This may result in engagement of nervous system regulation of social behaviors resulting in both in the moment and long term engagement of the sympathetic nervous system. The proposed 2-year research plan will examine the behaviors and nervous system reactions of individuals across loneliness levels in an experimental condition that manipulates the probability of engaging in relationship building behaviors.

This study will recruit 60 individuals aged 18-25 who are fluent in English and report no history of cardiovascular or respiratory disease to participate in a study investigating social interactions. While a specific level of loneliness is not an inclusion variable, to ensure representation across loneliness levels, the investigators will screen for levels of loneliness and invite individuals to participate equally distributed between 4 levels of loneliness: 1 or more standard deviations below the mean, between 0-1 standard deviations below the mean, between 0-1 standard deviations above the mean, and 1 standard deviation or more above the mean.

The study will then utilize a 2x2 factorial design splitting participants into reporting above or below the mean level of loneliness and randomizing those individuals to a behavioral task condition that involves answering either a high disclosure or low disclosure set of questions. Before engaging in the behavioral task, participants will fill out a series of questionnaires assessing their current social functioning. Participants will then have baseline levels of sympathetic nervous system and parasympathetic nervous system engagement measured. In an ongoing way, throughout the behavioral task, participants will have their of sympathetic nervous system and parasympathetic nervous system engagement measured. Every 15 minutes, the behavioral task will stop and participants will complete a series of questionnaires assessing their evaluation of their behavior with the research assistant in the task, as well as feelings of connection they are experiencing with the research assistant. At the conclusion of the behavioral task, participants will be invited back to participate in the condition they had not previously completed with a new research assistant. All behavioral tasks will be coded by trained research assistants assessing third party evaluation of relationship building behaviors.