Extended Project Qualification Essay Sample

Project Title#

Why are neurobiological theories relevant in the prevention of suicide and suicidal ideation?

Introduction and Key Definitions#

Suicide is one of the leading causes of death, both domestically and internationally, even more so than homicide. It is often, but not always, preceded by self-injurious behaviour and previous non-fatal suicide attempts, as shown in Figure 1 [omitted], also further contextualised by the contents of this paper. The World Health Organization (2021) reports that over 700,000 people die by suicide each year. Despite this, the academic study of suicide is generally limited in its scope.

Neurobiology is one of the ways humans can gain valuable insights into how the state of suicidality can arise, and by identifying what the suicidal brain looks like, it is possible to devise potential treatments, for example, by way of pharmacological means (i.e., authorised drugs). Neurobiology can be used to devise predictors of suicide, which is essential towards prevention.

The definitions of the titular terms of this paper must be made clear to contextualise the concepts that will be explored. The National Institute of Mental Health (2023) defines the term ‘suicide’ as ‘death caused by self-directed injurious behaviour with intent to die as a result of the behaviour’. Comparatively, there is no universally agreed definition as to what ‘suicidal ideation’ constitutes, but the broad definition that is accepted for the purposes of this research paper is, ‘a range of contemplations, wishes, and preoccupations with death and suicide’ (Harmer et al., 2021).

This paper aims to explore major findings within neuroscience, and, specifically, biological developments with relation to suicide and suicidal ideation. Additionally, it brings to light the fundamental limitations of neuroscience and why suicidology, as an academic discipline, is difficult to explore empirically rather than theoretically.

A summary of the existing research is needed before proceeding, which will be satisfied by the literature review after this introduction. Before the brain can be explored with its central relevance to suicide and associated treatments that derive from our understanding of it, the theoretical basis of the formation of suicidal thoughts must be given consideration through the stress-diathesis model. This paper will then discuss the serotonergic system and its involvement in suicidality. After, it will discuss imaging studies of the brain and how these have contributed to preventative efforts. Predictive coding also plays a major role in suicide as it relates to the cognitive framework humans have about the world around them, and how these can be distorted when suicide risk factors are present. The field of neuroscience, while at the highest point it has ever been, is limited about how scientific methodologies can be used to make advancements in research, both with relevance to suicide specifically and on a more general level. This will be discussed as the penultimate point. Finally, conclusions will be made about how neuroscientific developments thus far have advanced suicide research.

Literature Review#

In 1986, Donald H. Rubinstein published a stress-diathesis theory of suicide, which recognises the roles of both nature and nurture as contributors to the formulation of a suicidal state. That is to say that, to some extent, humans are predisposed to risk of suicide based on their DNA and hereditary factors, while at the same time, our upbringing and the environment that surrounds us contribute to this risk. Rubinstein recognised that it seemed wholly antithetical that the brain would allow for self-destructive behaviour, in recognition of the human species’ evolutionary instinct to stay alive that has developed over millions of years. The stress-diathesis theory of suicide is intended to explain how such a deviation can be explained scientifically.

This stress-diathesis theory of suicide was further developed by Mann and Arango (1992), who created a stress-diathesis model of suicide which aimed to integrate neurobiology and psychopathology into a cohesive model. It includes the relationship of psychopathological factors such as severity of depression and anxiety. Jollant et al. (2008) later investigated a stress-diathesis model by using participants with previous suicide attempts and non-suicidal controls (i.e., people who do not have diagnosed psychiatric disorders). Suicide attempters showed greater activity in the right lateral orbitofrontal cortex and decreased activity in the right superior frontal gyrus in response to angry versus neutral faces. This supports the explanation that suicidal behaviour is characterised by abnormalities in the brain.

Van Heeringen (2018) summarised the most major developments in brain neuroimaging studies relating to suicide in his book, The Neuroscience of Suicidal Behavior, including, but not limited to, the role of serotonin in the suicidal state, grey and white matter lesions and imaging of risk factors, some of which are more prominent in children as their brains are not fully developed.

Markram (2013) investigated the limitations of the field of neuroscience. It is notable that limitations are expressed in terms of neuroscience rather than neurobiology specifically, as they are more general, and specificity would not be helpful as they could apply equally to related fields such as neurochemistry. The single most important limitation is the simulation of the brain and how this is a task that is increasingly difficult, even as humanity’s knowledge of the brain continues to increase.

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