A Neural Basis for the Acquired Capability for Suicide

Abstract

The high rate of fatal suicidal behavior (SB) in men is an urgent issue as highlighted in the public eye via news sources and media outlets. In this study, we have attempted to address this issue and understand the neural substrates underlying the gender differences in the rate of fatal SB. The Interpersonal–Psychological Theory of Suicide has proposed an explanation for the seemingly paradoxical relationship between gender and SB, i.e., greater non-fatal suicide attempts by women but higher number of deaths by suicide in men. This theory states that possessing suicidal desire (due to conditions such as depression) alone is not sufficient for a lethal suicide attempt. It is imperative for an individual to have the acquired capability for suicide (ACS) along with suicidal desire in order to die by suicide. Therefore, higher levels of ACS in men may explain why men are more likely to die by suicide than women, despite being less likely to experience suicidal ideation or depression. In this study, we used activation likelihood estimation meta-analysis to investigate a potential ACS network that involves neural substrates underlying emotional stoicism, sensation-seeking, pain tolerance, and fearlessness of death, along with a potential depression network that involves neural substrates that underlie clinical depression. Brain regions commonly found in ACS and depression networks for males and females were further used as seeds to obtain regions functionally and structurally connected to them. We found that the male-specific networks were more widespread and diverse than the female-specific ones. Also, while the former involved motor regions, such as the premotor cortex and cerebellum, the latter was dominated by limbic regions. This may support the fact that suicidal desire generally leads to fatal/decisive action in males, while, in females, it manifests as depression, ideation, and generally non-fatal actions. The proposed model is a first attempt to characterize the neural networks underlying gender differences in SB. Future studies should examine the proposed network to better characterize and refine this network using tasks specifically targeted toward constructs underlying ACS.

Imaging suicidal thoughts and behaviors: a comprehensive review of 2 decades of neuroimaging studies

“…Although the involvement of the insula in STBs has had little direct research focus, its critical involvement in interoceptive processing, detecting salient internal and external stimuli, experiencing emotion, and self-awareness [174][175][176] suggests an important role of the insula in SI. In addition, the insula is implicated in disconnection from bodily experiences, which in turn may lower the threshold to engaging in behaviors that harm the body (in line with the acquired capability theory [177]) thus suggesting a role of the insula in suicide behaviors. In line with important roles of dACC and insula circuitry (as part of the "salience network") in mediating or switching between the extended VMPFC (default mode, affective, reward) systems and the DPFC/IFG (executive control) system [178][179][180], the dACC and insula may represent integral hubs that facilitate the transition from SI to attempt.…”

Gray Matter Volume Alterations Associated with Suicidal Ideation and Suicide Attempts in Patients with Mood Disorders

“…In addition, schizophrenia patients with a history of suicide attempts showed signi cant volumetric associations with the left middle frontal gyrus [32]. The acquired capability for suicide networks in males consisted of the middle frontal gyrus [33]. A pilot study of differential brain activation to suicidal means and DNA methylation of the CACNA1C gene in SA patients, found that the left middle frontal gyrus was shown to have signi cantly higher brain activation in the SA patients than the controls [34].…”

Female Gender, Marital and Family Problems, and Feelings of Guilt Are Related to Self-Immolation Suicide Attempts

“…Rather, we agree with Campbell and Guiao [41], who claimed that SI as a demonstrative act (carried out in front of others) can entail the intention to induce guilt and shame among close family members in particular. Additionally, lack of fear of death [25] in combination with a sort of copycat effect [11, 12, 33], along with the availability of fluid accelerants and the presence of psychiatric disorders (especially adjustment disorders) may be factors with the potential to deepen our understanding of the psychosocial and psychological conditions favorable to committing suicide by SI.…”

“…Further, in a previous study [24] we were able to show that early maladaptive schemas of emotional deprivation, social isolation, shame, and abandonment were related to a history of suicide attempts among patients with major depressive disorders. Additionally, attempting and committing suicide implies behavior-inducing cognitions such as emotional stoicism, sensation-seeking, pain tolerance, and lack of fear of death [25]. …”