The Implication of 5-HT Receptor Family Members in Aggression, Depression and Suicide: Similarity and Difference

Being different multifactorial forms of psychopathology, aggression, depression and suicidal behavior, which is considered to be violent aggression directed against the self, have principal neurobiological links: preclinical and clinical evidence associates depression, aggression and suicidal behavior with dysregulation in central serotonergic (5-HT) neurotransmission. The implication of different types of 5-HT receptors in the genetic and epigenetic mechanisms of aggression, depression and suicidality has been well recognized. In this review, we consider and compare the orchestra of 5-HT receptors involved in these severe psychopathologies. Specifically, it concentrates on the role of 5-HT(1A), 5-HT(1B), 5-HT(2A), 5-HT(2B), 5-HT(2C), 5-HT(3) and 5-HT(7) receptors in the mechanisms underlying the predisposition to aggression, depression and suicidal behavior. The review provides converging lines of evidence that: (1) depression-related 5-HT receptors include those receptors with pro-depressive properties (5-HT(2A), 5-HT(3) and 5-HT(7)) as well as those providing an antidepressant effect (5-HT(1A), 5-HT(1B), 5-HT(2C) subtypes). (2) Aggression-related 5-HT receptors are identical to depression-related 5-HT receptors with the exception of 5-HT(7) receptors. Activation of 5-HT(1A), 5-HT(1B), 5-HT(2A), 5-HT(2C) receptors attenuate aggressiveness, whereas agonists of 5-HT(3) intensify aggressive behavior.