Understanding and Preventing Violence, Volume 2: Biobehavioral Influences (1994)
Chapter: Dopamine
Other Hormones
Steroids are not the only hormones that have been related to aggression and violence, but other hormones appear to have less direct or less specific effects. For example, adrenal norepinephrine secretion has been related to the commission of violent crime, but norepinephrine and epinephrine are released in response to a wide variety of arousing or emotional conditions and are important in coping with stress. Animal and clinical studies have found evidence for a role of central nervous system (CNS) norepinephrine in aggressiveness—but when it acts as a neurotransmitter, not as a hormone. Because hormones can alter many aspects of cellular activity and because aggressive behavior involves so many areas of the brain, the potential for indirect or secondary effects of hormones is high.
In summary, there is no simple relationship between hormones and aggression, much less violence. The strongest conclusion is that in humans, steroids can influence and be influenced by aggressive behavior. However, they are only one influence of many and not the determining factor. The opposite relationship (i.e., the environment and behavior influence on hormone secretion) is the stronger of the two linkages.
NEUROTRANSMITTERS AND RECEPTORS
Dopamine
Evidence from animal studies points to large changes in brain dopamine systems during aggressive or defensive behavior. At present, evidence for similarly altered dopamine activity in brain regions of violent humans is not available. It is possible that brain dopamine systems are particularly significant in the rewarding aspects of violent and aggressive behavior. However, at present, a "marker" for some aspect of brain dopamine activity that is selective to a specific kind of aggression or violent behavior has not been identified in any of the accessible bodily fluids or via imaging methods in the brain.
The most frequently used treatment of violent outbursts in emergency situations and also in long-term medication of violence-prone individuals employs drugs that act principally at dopamine receptors. Particularly, drugs that antagonize the D2 subtype of dopamine receptors represent widely used antipsychotics with frequent application to violent patients. Evidence from animal and human studies emphasizes the many debilitating side effects of these drugs
