Résumé
Suicidal behaviors (i.e. suicide and suicide attempt (SA)) are a major public health issue. These lasts were mainly considered as a consequence or a symptom of a comorbid psychiatric disorder leading to a lack of specific treatments. However, recent studies suggest that suicidal behaviors could have their own physiopathology and that suicidal depression (i.e. depression with suicidal ideation and/or SA) could be a specific subtype of depression. Thus, there is a need to better understand this physiopathology to find new therapeutic strategy. Deregulation of the opioid system has been suggested to be involved in suicidal behavior. As beta-endorphin (Beta-End) is the main endogenous ligand of the mu opioid receptor, it is pertinent to explore the link between levels of Beta-End and suicidal behaviors to better understand the involvement of the opioid system in this disorder. Research on Beta-End in suicidal patients remains scarce. Thus, the aim of this manuscript was to review studies on the association between Beta-End levels and suicidal behavior and psychiatric disorders associated with suicidal behavior (i.e. non-suicidal selfinjury, depression, and post-traumatic stress disorder). There are currently few data on Beta-End levels within suicidal patients. However, according to these studies it seems that plasmatic levels of Beta-End are decreased within suicidal patients. Interestingly, these levels seem to increase with higher number of SA, that could explain an "addiction" to SA may be to relieve psychological pain by increasing levels of Beta-End, as suggested by some authors. Studies suggest a deregulation of the opioid system within suicidal patients. More studies are needed to better understand this deregulation and to find new therapeutic target. Research on the opioid system in suicidal behaviors seems to represent a primordial and future axis of research.