Neurobiology of aggression and violence

Abstract

Acts of violence account for an estimated 1.43 million deaths worldwide annually. While violence can occur in many contexts, individual acts of aggression account for the majority of instances. In some individuals, repetitive acts of aggression are grounded in an underlying neurobiological susceptibility that is just beginning to be understood. The failure of "top-down" control systems in the prefrontal cortex to modulate aggressive acts that are triggered by anger provoking stimuli appears to play an important role. An imbalance between prefrontal regulatory influences and hyper-responsivity of the amygdala and other limbic regions involved in affective evaluation are implicated. Insufficient serotonergic facilitation of "top-down" control, excessive catecholaminergic stimulation, and subcortical imbalances of glutamatergic/gabaminergic systems as well as pathology in neuropeptide systems involved in the regulation of affiliative behavior may contribute to abnormalities in this circuitry. Thus, pharmacological interventions such as mood stabilizers, which dampen limbic irritability, or selective serotonin reuptake inhibitors (SSRIs), which may enhance "top-down" control, as well as psychosocial interventions to develop alternative coping skills and reinforce reflective delays may be therapeutic.

FIGURE 1

Susceptibility to Aggression and Psychiatric Diagnosis

FIGURE 2

Initiation and Modulation of Aggression^{a a} Figure adapted/modified with permission from S.J. DeArmond et al., “Structure of the Human Brain: A Photographic Atlas, Third Edition” [Oxford University Press, New York, 1989]. Copyright © Oxford University Press. A modified version of this figure appeared in Davidson et al., Science 2000; 289:591.

FIGURE 3

Brain Circuitry and Neuromodulators Regulating Aggression Brain Circuitry

FIGURE 4

Pretreatment Abnormalities in the Pathophysiology of Aggression^{a a} Figure adapted/modified with permission from S.J. DeArmond et al., “Structure of the Human Brain: A Photographic Atlas, Third Edition” [Oxford University Press, New York, 1989]. Copyright © Oxford University Press. A modified version of this figure appeared in Davidson et al., Science 2000; 289:591.

FIGURE 5

Posttreatment Abnormalities in the Pathophysiology of Aggression^{a a} Figure adapted/modified with permission from S.J. DeArmond et al., “Structure of the Human Brain: A Photographic Atlas, Third Edition” [Oxford University Press, New York, 1989]. Copyright © Oxford University Press. A modified version of this figure appeared in Davidson et al., Science 2000; 289:591.

FIGURE 6

Mechanisms of Aggression in Different Psychiatric Disorders

FIGURE 7

Neurobiological Implications for Pharmacotherapy of Aggression