The Serotonergic Dimension of Aggression and Violence

Investigations of the mechanisms underlying impulsivity (individual tendency toward impulsive behavior) and aggressiveness (individual tendency toward aggressive behavior) seek to determine the neurobehavioral factors that underlie violence or other destructive behaviors in humans. Behavioral, imaging, pharmacologic, and genetic studies indicate that anatomically and functionally distinct neural circuits, as well as numerous neurotransmitters, growth factors, hormones, and their intracellular signaling effectors, influence impulsivity and aggressiveness in animal models and humans (Lesch and Merschdorf, 2000). Aggression is an umbrella term for various facets of aggressive behavior, which ranges from the establishment of hierarchies and dominance to antisocial behavior and delinquency. In both humans and animals, the term aggression comprises a variety of behaviors that are heterogeneous for neurobiological features and clinical phenomenology. Although most neurobiological studies of aggression and violence typically do not differentiate between premeditated and impulsive aggression, which is relatively unplanned and spontaneous but often culminates in physical violence, this distinction is likely relevant in understanding their genetic, functional neuroanatomical, and neuro-chemical bases.