Neuro-Biochemical Dysregulation – The Silent Suicidal Agent

Suicide has become a social and global menace. It has turned out among the leading causes of mortality worldwide. Though numerous issues have been implicated with its occasion and prevention, neuro-biochemical concern has been less pronounced. This article is the neuro-biochemical cross-talk with suicide.

Suicide, a global burning issue, encompass multiple facets of causative and affective factors [1]. Personal, social, mental, economical and career-based issues of different sorts have been linked with suicidal trends and practices [2]. Little concern has been focused on the neuro-biochemical hallmarks of suicide, attempts to suicide and associated preventive measures. Thus, the present article has been aimed at delving out the neuro-biochemical implications of suicide followed by preventive recommendations.

Involvement of central nervous system in suicidal attempt

Thirty-seven years long studies on the Danish suicide victims reveal that the people suffering from neurological disorders are at 75% increased risk of committing suicide than their healthy counterparts [3]. Neurological disorders like Alzheimer’s disease (AD), dementia, Parkinson’s disease (PD), stroke, epilepsy, head injury pose grave threat towards development of suicidal tendency [3]. Besides, anxiety and depression are two alarming risk factors of suicide [3].

Serotonin and serotonergic brain circuit

Serotonergic brain circuits have directly been implicated in depression and suicide [4].

Decreased level of serotonin (5-hydroxy tryptamine, 5-HT) in the brain is among the most notorious causes of anxiety and depression [5]. Level of serotonin metabolite 5-hydroxy indole acetic acid (5-HIAA) in the cerebrospinal fluid (CSF) also affects serotonergic activity [6]. Diminished serotonergic activity leads towards increased aggressive and impulsive behaviour as well as murderous and suicidal tendencies [7].

Norepinephrine

Role of norepinephrine (NE) has been found to be opposite of that of the serotonin i.e. increased NE levels tends towards aggressive and suicidal attempts and vice versa [8].

Dopamine

Level of dopamine have been positively correlated with aggression and suicidal attempt [9].

Hypothalamic-Pituitary-Adrenal Axis

The neuroendocrine system, hypothalamic-pituitary-adrenal (HPA) axis regulates the body’s response to stress [10]. It maintains the interactions among brain serotonergic, noradrenergic, and dopaminergic systems [11]. Stress induces the release of the corticotrophin releasing hormone (CRH) that activates the HPA axis through release of adrenocorticotropin (ACTH) from the pituitary [12]. Consequently, corticosteroids are released from the adrenal glands that result in behavioural alterations [12]. Hyperactivity of the HPA axis has been linked with the suicidal behaviour [13].

Neuro-genetics

Increased expression of the 5-HT2A receptor in the pre-frontal cortex of the suicide victims indicate the possible neuro-genetics link [14]. Also, differential expression of the serotonin transporter (5-HTT) gene has been observed in the brain autopsies of the suicide victims [15]. Similar anomalies have been implicated in the genes of monoamine oxidase (MAO) and catechol-o-methyl transferase (COMT) [16].

Neuro-inflammation

Neuro-inflammation is another hallmark of suicidal brain [17]. Abnormal level of neuro-pro-inflammatory factors have been observed in the brains of the suicide victims [18]. Besides, altered activities of the neuroglial cells, especially of the astrocytes, have been observed [19]. Abnormal morphology of the astrocytes such as increased cell body warrant attention [20].

Rate of suicide has been soaring worldwide. Time is up for focusing on neuro-biochemical phenomena with a view to maintaining sound physico-psycho state of the individuals. In this aspect, care should be taken to let the neurobiochemical activities at their balanced and healthy state. Let the health-care professionals, policy makers and care givers of the neurologically ill persons be concerned and take necessary steps for the stated concern.

Authors gratefully thank Jahangirnagar University and the University Grants Commission (UGC) of Bangladesh for providing all the supports.

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