The Neuroscience of: Suicidal behaviour

The Neuroscience of: Suicidal behaviour

Shail Bhatt discusses the underlying neuroscience of suicidal behaviour and multiple factors in the brain which can contribute to it.

This article is particularly close to my heart and is dedicated to my cousin, who took his own life after suffering from depression. He was a talented poet, a doting son and had a bright future ahead in journalism and media communications. After hearing the news, I just kept on thinking to myself: Why would he do this? Didn’t he know how much his family and friends loved him and supported him? That rationale got me researching about suicidal thoughts, and how the wicked interaction of your inner and outer environments can seriously hamper your rational mindset.

The interplay between the external environment and internal conflict can misdirect and influence mood and behaviour, leading to affective disorders, such as depression, anxiety, and bipolar disorders. Affective disorders tend to distort reasoning, and there are several different types of cognitive distortions that may arise, such as thinking in black-and-white, or magnifying one’s own defects and shortcomings, negatively comparing oneself to others, and labelling oneself in self-deprecatory and derogatory ways. For example, a single mistake would cause the individual to consider himself or herself as the root cause of that event; as the failure of situation. This tends to exacerbate and intensify the feelings of pain, guilt and self-aggression.

There are three characteristics that lead an individual to have suicidal tendencies: experiencing events that are a sign of defeat or of a “loser” status, the feeling of being trapped, and the feeling of not being able to be saved, which makes an individual feel incapacitated. The accumulation of these events often leads to the worst. But despite being such a vicious and cruel thing, suicidal behaviour is still not fully understood.

Based on preliminary research, it has been seen that a lack of metabolites needed to synthesize serotonin (a neurotransmitter crucial for controlling mood, appetite, and sleep) in the spinal fluid has been linked to increased impulsivity and self-directed aggression. Similarly, dysfunction of the serotonin function can also cause hopelessness and neurotic behaviour. In addition, lower levels of noradrenaline-producing neurons, have been known to be seen in individuals who die by suicide.

Facing difficulties or stressful events in childhood increases the risk of suicide due to modifications in neurotransmitter release, which alter mood and influence decision making. One example of this is childhood adversity causing excessive noradrenaline release in these fewer neurons. This excessive noradrenaline secretions, in turn, causes the depletion of the neurotransmitter; this depletion of noradrenaline (along with dopamine) has been linked with increased self-aggression.

Apart from neurotransmitters, several other smaller proteins involved in cell signalling, called cytokines, can also lead to increased negative and incapacitated behaviour. Interferons and interleukins, for example, are cytokines that help with the immune response against infections, and can be used to treat certain types of cancer. However, they have been known to cause depression a month into therapy. Further research showed that suicide victims had higher concentrations of these cytokines; these may modulate the release of neurotransmitters like serotonin, may cause the release of compounds like quinolinic acid, and may modulate several important hormonal pathways which increase depression and instigate suicidal thoughts.

The effects of altered hormonal pathways can also result in increased suicidal tendencies. The hypothalamic-pituitary-adrenal (HPA) axis is one such mechanism that is particularly important in regulating stress. It may be overactivated, leading to an increase in cortisol and related corticosteroids. These hormones may, in turn, causes changes in the levels of serotonin and noradrenaline, which causes mood changes and hence suicidal thoughts.  In addition, stress in childhood adversity causes a reduction in another protein, brain-derived neurotrophic factor (BDNF), which is needed for the growth and survival of neurons. Changed levels of BDNF may be linked to depression and suicidal behaviour, although the exact relationship is not known.

We often feel that suicide is unexplained. But the chemicals in our body prove that it is something that builds up. 800,000 people die from suicide every year, and learning more about the neuroscience behind it may aid us in helping those in risk. Maybe then, there would be no more incomplete stories and unfinished poems.

It’s never too late to ask for help, and if you have suicidal thoughts, please contact the UCL Student Support and Wellbeing advisers at student.wellbeing@ucl.ac.uk or call them at +44 (0) 20 7679 0100.

Image Credit: pixabay

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