Staring Down Death

Eyes Fixed on Heaven's Gate: An Empirical Examination of Blink Rate and Suicide

Anecdotal and theoretical work suggests blink rate as an indicator of imminent suicide risk. We sought to empirically examine whether suicide decedents displayed a reduced blink rate in goodbye videos filmed before death, compared to several control groups. Independent raters coded blink rates from videos of 34 suicide decedents and four comparison groups: "mundane" product review, non-suicidal arousal, non-suicidal depression, and non-imminent risk of suicidal ideation. Mean blink rate was lower in the suicide decedent group relative to all comparison groups (ps < .001), except the depressed (p = .976) and suicidal ideation (p = .393) groups. Findings indicate blink rate may be reduced among individuals at imminent risk for suicide, exhibiting clinically-significant depressive symptoms, or experiencing suicidal ideation.

Blink rate as a measure of stress and attention in the domestic horse (Equus caballus)

Measuring animal stress is fundamentally important for assessing animal emotional state and welfare. Conventional methods of quantifying stress (cortisol levels, heart rate/heart rate variability) require specialist equipment and are not instantly available. Spontaneous blink rate (SBR) has previously been used to measure stress responses in humans and may provide a non-invasive method for measuring stress in other animal species. Here we investigated the use of SBR as a measure of stress in the domestic horse. SBR was measured before and during a low-stress event (sham clipping) and compared with heart rate variability and salivary cortisol. For the entire sample, there was a reduction in SBR (startle response) during the first minute of clipping. For horses reactive to clipping, the initial reduction in SBR was followed by an increase above baseline whereas the SBR of the non-reactive horses quickly returned to baseline. For the entire sample, SBR correlated with heart rate variability and salivary cortisol. We have demonstrated that SBR is a valid fast alternative measure of stress in horses, but the initial 'startle' response must be considered when using this parameter as a measure of animal stress.

Suicidal ideation, suicide attempts, and neurocognitive dysfunctions among patients with first-episode schizophrenia

OBJECTIVE

To determine whether suicidal ideation or suicide attempts are linked to poor neurocognitive function among individuals with first-episode schizophrenia (FES).

METHOD

We performed a cross-sectional study on 159 Chinese inpatients (M_age  = 27.1 years; 52.2% females) with minimal-treated FES and collected their suicidal history through interviews and medical records. Neurocognitive performance, psychopathology, and depressive symptoms were assessed using the MATRICS Consensus Cognitive Battery, the Positive and Negative Syndrome Scale, and the Calgary Depression Scale for Schizophrenia, respectively.

RESULTS

Approximately 1/10 FES inpatients had any suicide attempts, and more than 1/4 reported lifetime suicidal ideation. Inpatients with a suicide attempt or suicidal ideation scored significantly worse in the overall seven neurocognitive domains compared with those without past suicidal ideation or a suicide attempt. Linear regression suggested that suicide attempts were mainly associated with lower scores in working memory and speed of processing, after adjusting for education levels. The associations remained robust after further controlling for psychopathological and depressive symptoms.

CONCLUSION

First-episode schizophrenia patients with suicide attempts had more severely impaired neurocognitive performances in specific domains. Fundamental neurocognitive dysfunctions should be assessed, detected, and treated after their suicide risk assessments.

Etiopathogenesis of Suicide: A Conceptual Analysis of Risk and Prevention Within a Comprehensive, Deterministic Model

Suicide is a rising global health concern receiving disproportionate attention in comparison to other health conditions. In spite of substantial technological and scientific advancements, suicide research has continued to move slowly in terms of clinical translation due to the complexity of neural mechanisms, and subjective experiences that seem to underpin this complex human behavior. This paper analyzes the concepts of risk and prevention in the context of suicide in an attempt to bridge the large methodological and theoretical gaps between the biological, psychological, and sociological dimensions. This paper aims to accomplish the following objectives: (1) operationalize the concepts of suicide risk and prevention as they relate to current knowledge and capabilities; (2) synthesize and integrate suicide research across biological, psychological, and sociological dimensions; (3) discuss limitations of each dimension in isolation; (4) suggest a model of etiopathogenesis that incorporates extant literature and bridges unnecessary gaps between dimensions; and (5) suggest future directions for multidimensional research through the inclusion of principles from the physical sciences. Ultimately, this paper provides a basis for a comprehensive model of suicide within a deterministic, chaotic system.

Differentiating suicide attempts and suicidal ideation using neural markers of emotion regulation

BACKGROUND

Theories of suicide posit distinct etiological pathways for suicide attempts (SA) and suicidal ideation (SI) that are marked, in part, by disruptions in the ability to regulate reactions to threat/mutilation and interpersonally-relevant emotional stimuli. However, little research has specifically tested these associations. To address this gap, the present study extracted the Late Positive Potential (LPP) during an emotion regulation task to evaluate the independent associations that SA history and SI share with initial responsivity to, and regulation of, these distinct emotional contents.

METHODS

A clinical sample (N = 257) were recruited based on elevations in suicide risk factors. Participants completed a picture viewing and regulation task that included threat/mutilation, reward, and neutral images from the International Affective Picture System. Immediately prior to picture onset, participants were instructed to passively view the image, increase their emotional reaction to the image, or decrease their emotional reaction to the image.

RESULTS

Differential patterns of LPP amplitudes only emerged in the context of attempts to regulate emotional responses such that SA history predicted a superior ability to volitionally mitigate responses to threat/mutilation while SI was related to a worse ability to increase responses to reward. Effect sizes were in the small and small-to-medium range.

LIMITATIONS

The present data were cross-sectional and included low trial counts.

CONCLUSIONS

Taken together, these findings support existing theories of suicide suggesting that distinct mechanisms underlie suicidal thoughts and behaviors. Future research should seek to determine if these mechanisms may serve as a viable intervention targets.

Evolutionary processes in suicide

Suicidal behavior contains several dynamic elements. Due to its complexity, empirical science may approach suicide through various avenues. One underutilized approach is taking an evolutionary perspective. Our review of the literature presents two evolutionary processes that may be implicated in suicidal behavior, namely eusocial behavior and antipredator response behaviors. Studies have indicated that aspects of suicidal behavior parallel self-sacrificial behavior in eusocial animals, and that systems similar to hyperarousal-shutdown systems involved in antipredator behaviors may be activated among suicidal individuals. Research on brain activity and decision-making processes among suicidal individuals also suggests that eusociality and antipredator response behaviors in suicide may not be mutually exclusive. These processes represent novel sources of information and potential solutions regarding suicide.

Can the Phenomenology of a Suicidal Crisis Be Usefully Understood As a Suite of Antipredator Defensive Reactions?

When perceiving a dangerous predation threat, mammalian and other species activate antipredator defensive reactions. These include the seemingly paradoxical-but compatible-activation of overarousal (e.g., agitation, insomnia) and "shutdown" (e.g., mutism, withdrawal) states. Acute suicidal crises, too, are characterized by the co-occurrence of overarousal and shutdown behaviors. In the minutes, hours, and days prior to one's death by suicide, it is not uncommon for one to be simultaneously agitated and socially withdrawn, states that resemble antipredator defensive reactions. In this article, we present empirical, clinical, and philosophical grist for our conjecture that antipredator defensive reactions may serve as a useful way to understand the phenomenology of a serious suicidal crisis, and we reflect on the implications that soon-to-be suicide decedents are simultaneously killer and victim.