Implicit Measures of Extreme Psychological Distress in Young Healthy Adults: Cardiac Autonomic Activity and Attentional Bias

Background: There is research showing that cardiac sympathetic autonomous activity is elevated and cardiac parasympathetic autonomous activity is decreased in individuals contending with serious psychopathology. There is also work showing that attentional bias to emotionally distressing stimuli is affected by depression and anxiety. This study hypothesized that individuals who were high on suicide-related attention bias (AB) and cardiac sympathetic activity (SNS index) would also have elevated psychological distress, even in the absence of a diagnosable disorder. Methods: Participants were 181 healthy college students, 42.5% male. Personality traits, depression, hopelessness and suicidal ideation/behaviour were self-reported. Cardiac activity was measured using bodyguard2, and the SNS index was used as a measure of stress. AB was measured using stimuli salient in the context of death and suicide. Results: Correlations were in the expected direction. Cluster analysis using AB and the SNS index produced three clusters, of which Cluster 3, 19.7% of the sample, had elevated AB and SNS index, and by far the most distressed psychological profile, above the clinical cut-off point for depression. Conclusions: The study results indicate a strong association between objective and subjective measures of distress uncovered by cluster analysis. Such result may help to identifying a group of extremely distressed individuals among healthy adults. Individuals with a distressed personality profile, who are depressed and reject life, can be distinguished by their cardiac stress and AB.