关键词: 厌恶情绪, 死亡本能, 基本情绪, 抑郁, 自杀行为

Abstract:

Suicide is the primary cause of adolescent death, and suicide seriously endangers the life security and mental health of human being. Suicidal behavior includes suicidal ideation, suicidal attempt and suicide. Suicidal ideation refers to serious suicidal thoughts of preparing for a fatal, self-directed, and potentially injurious behavior, or refers to the intension to die without specific plans. Suicidal attempt refers to the intension to commit suicide, including the plans for suicide and even committed suicide; they might attempt to attract attention through bodily harm, but not necessarily causing actual harm. However, suicide is self-directed harm or death. According to suicidal theories which were based on the ideation-to-action framework, self-disgust is a key factor for the formation of suicidal ideation. This article reviews theoretical basis, correlation factor and neurophysiological mechanism of disgust induced suicidal behavior, and predicts future research direction.

Many recent studies suggested that many psychological problems, including suicide, are caused by patients' disgust to the surroundings and the environment. Disgust is a basic emotion, which is a response to disgustful things, and it is a defensive mechanism to keep people away from spoiled foods or from pollutants to prevent potential diseases, viruses and pollution. However, under heavy burdens and pressures, people would feel depressed and self-disgust, and ultimately lead to despair (extreme self-disgust), resulting in suicidal ideation. Under the condition of having suicidal ability, suicidal ideation would turn to be suicidal attempts, and thus suicide.

It is also suggested that early life trauma might be the root for disgust inducing suicidal ideation. And life stress and mental illness might aggravate the induction of disgust to suicide. High-intensity self-disgust has been proved to be the most relevant predictor of suicidal risks in mental illness. Psychoanalysis shows that when people are disgusted by themselves, the aggression behavior induced by disgust would also be directed to themselves, so self-disgust might induce suicide.

The neural mechanism of self-disgust inducing suicide may be related to monoamine (including serotonin) and oxytocin. Hypothalamic-pituitary-adrenal (HPA) axis are related to the stress response system that plays a very important role in disgust-induced suicidal ideation. Besides, self-disgust may be affected by traumatic stresses in early life, current psychological problems and mental diseases, which might lead to the mal-development of 5-hydroxytryptamine (5-HT) system, that determines the pattern of stress response in adulthood, including suicide.

However, there are still some limitations in current suicide studies. First of all, most studies are still limited to cross-sectional design and cannot compare time factors. Therefore, future studies should adopt vertical design and prospective research. Secondly, since most studies are limited to questionnaire studies, future studies could apply neuroscience technologies, such as neuroimaging and electrophysiology, in investigating the neural mechanisms of suicidal behavior, as well as the psychological and neural mechanisms of suicidal behavior affected by disgust.

Key words: disgust, death instinct, basic emotions, depression, suicidal behavior