Translational research in suicide: Is it possible to study suicide in animal models?

Suicide constitutes a serious medical and social problem. There are several risk factors for suicide including history of mental disorders, alcohol and substance abuse, impulsive or aggressive tendencies, family history of suicide, family history of child maltreatment, previous suicide attempts, feelings of hopelessness, cultural and religious beliefs, and physical illness, in particular chronic pain. Up to date, there are no animal models of suicide mainly because there is no instance of suicide among animals. Indeed suicide occurs almost exclusively in humans giving the link to two important aspects of the human being: (1) the self- consciousness and (2) the psychological suffering. However, in experimental animals we can model several of the main risk factors for suicidal behavior. In this chapter we will thus describe the main animal paradigms of mood disorders, aggression, impulsivity, and drug abuse/dependence. Moreover, we examine the in-vivo electrophysiology technique which allows the study of the neural activity of the different neurotransmitters implicated in suicide. The combination of behavioral pharmacology and electrophysiology is currently a gold standard for the investigation of the neurobiology of mental illness and has allowed answering clinically relevant questions and developing novel and efficacious treatments in psychiatry. This approach may thus have great potential also in the field of suicide allowing to increasing our understanding of the neurobiological basis of suicide. However, to develop novel pharmacological strategies to prevent suicide attempts, more translational research in humans is needed to understand the link between depression, impulsivity, self-consciousness, and psychological suffering.