Fearlessness About Death is Related to Diminished Late Positive Potential Responses When Viewing Threatening and Mutilation Images in Suicidal Ideators

Pain tolerance and threshold in suicide attempters: A systematic review and meta-analysis

It has been hypothesized that individuals less sensitive to pain could be at higher risk of suicide. However, data on pain sensitivity in suicide attempters (SA) obtained using experimental procedures are heterogeneous. The aim of this systematic review and meta-analysis was to investigate and compare pain tolerance and threshold in SA (patients with lifetime history of suicide attempt), non-attempters (psychiatric controls, PC), and healthy controls (HC). A random effects meta-analysis was used to estimate the standardized mean differences using data from 16 studies that compared physical pain tolerance and threshold in SA and PC or HC. Pain tolerance and threshold were not significantly different in SA and PC. However, pain tolerance, but not threshold, was higher in SA than HC. Our findings do not support the hypothesis of an altered pain perception related as a trait for suicidal vulnerability, but rather suggest altered pain perception related to psychiatric vulnerability.

Neurophysiological Markers Related to Negative Self-referential Processing Differentiate Adolescent Suicide Ideators and Attempters

Background

Adolescent suicide is a major public health concern, and presently, there is a limited understanding of the neurophysiological correlates of suicidal behaviors. Cognitive models of suicide indicate that negative views of the self are related to suicidal thoughts and behaviors, and this study investigated whether behavioral and neural correlates of self-referential processing differentiate suicide ideators from recent attempters.

Methods

Adolescents with depression reporting current suicidal ideation and no lifetime suicide attempts (suicide ideators, n = 30) and past-year suicide attempts (recent attempters, n = 26) completed a self-referential encoding task while high-density electroencephalogram data were recorded. Behavioral analyses focused on negative processing bias (i.e., tendency to attribute negative information as being self-relevant) and drift rate (i.e., slope of reaction time and response type that corresponds to how quickly information is accumulated to make a decision about whether words are self-referent). Neurophysiological markers probing components reflecting early semantic monitoring (P2), engagement (early late positive potential), and effortful encoding (late late positive potential) also were tested.

Results

Adolescent suicide ideators and recent suicide attempters reported comparable symptom severity, suicide ideation, and mental disorders. Although there were no behavioral differences, compared with suicide ideators, suicide attempters exhibited greater P2 amplitudes for negative versus positive words, which may reflect enhanced attention and arousal in response to negative self-referential stimuli. There were no group differences for the early or late late positive potential.

Conclusions

Enhanced sensory arousal in response to negative stimuli-that is, attentional orienting to semantic, emotional, and self-relevant features-differentiates adolescent suicide attempters from ideators and thus may signal risk for suicidal behavior.