Understanding the neural basis of survival instinct vs. suicidal behavior: a key to decode the biological enigma of human suicidal behavior.

Suicidal behavior is a globally widespread psychiatric disorder with a high rate of mortality. Suicide causes psychological and economic hardships for the families and societies, necessitating the development of effective prevention and treatment programs. However, a clear understanding of the neural basis of suicidal behavior would be essential to develop clinically effective therapies. To date, several neurobiological studies have reported the genetic and epigenetic factors, brain regions, and neurotransmitters involved in suicidal behavior; but, a clear understanding of the origins of self-destructive tendencies is lacking. The high prevalence of self-destructive tendency, a potential hallmark of suicidal behavior presents a biological enigma in light of the evolutionarily pervasive struggle for existence and survival (self-preservation instinct). The potential neural correlates of suicidality and survival behavior have been separately investigated. Several regions of prefrontal cortex were implicated in suicide, while the survival circuits regulating the life-processes (defense, thermoregulation, energy and nutrition, fluid balance, and reproduction) include hypothalamus, amygdala, and parabrachial nucleus, among other structures. Future research to understand the possible influence of malfunctioning survival circuits in suicide could provide valuable insights into suicidal behavior. In addition, understanding the possible evolutionary significance of suicidal traits can help us understand the mechanisms of evolution, and also serve towards alleviation of social stigma around suicide. Thus, future research to unravel the biological correlates of survival vs. suicidal instincts, equipped with high-resolution neuroimaging techniques, would be clinically and socially advantageous towards suicide prevention and treatment.