Psychophysiology of anger and violent behavior

Antisocial behavior is a complex phenomenon that arises out of multiple causes involving biologic, psychological, and social forces. Moreover, different forms of violent antisocial behavior may each result from different biopsychosocial pathways. The overview of human psychophysiologic findings presented in this article provides some support for this notion. In particular, the finding of psychophysiologic underarousal (e.g., reduced resting HR and SC levels, increased slow-wave EEG, poor classical conditioning) is one of the most robust and best replicated findings in antisocial populations. The majority of these studies consist of populations exhibiting nonviolent antisocial behavior or milder forms of aggression. Findings of underarousal in institutionalized criminal samples are very few in number and are not well-replicated. The relationship of psychophysiologic underarousal to antisocial behavior, therefore, may be specific to covert forms of antisocial behavior and perhaps to some less severe forms of violent behavior. On the other hand, violence associated with anger and emotional aggression (which is often more impulsive, less controlled, and reactive to some perceived provocation) may have very different psychophysiologic underpinnings. It was suggested that risk factors for emotional aggression include a predisposition to negative affect/arousal and an inability to regulate that affect/arousal. It also was suggested that this effect will be most pronounced in individuals experiencing stressors or adverse social environments, where negative affect and arousal would be increased. Laboratory studies have suggested that overarousal may facilitate aggression in situations in which someone has been provoked. Clinical studies also have indicated a relationship between increased physiologic arousal, negative emotionality, and aggression/antisocial behavior in some populations, with increases in aggression in those also exposed to adverse home environments. Thus, the relationship of increased psychophysiologic arousal to antisocial behavior may be more specific to angry or emotional violence. It is important to note that these psychophysiologic distinctions are speculative for few studies actually have differentiated type of violence in their design. Pitts did group children according to proactive or reactive aggression and found reduced HR levels in both groups, but a substantial increase in HR only in the reactive aggressive group. Lakosina and Trunova found increased SC responsivity in psychopathic individuals characterized by affective violence. These studies provide some initial support for underarousal in proactive/instrumental aggression and overarousal in emotional aggression. It is important, however, that more studies be done with subtypes of violence to test the notion of such differential psychophysiologic patterns. Lastly, some definitional and methodologic considerations need to be mentioned. First, a distinction exists between physiologic arousal and reactivity. Typically, arousal refers to psychophysiologic activity that occurs during a resting state, whereas reactivity refers to activity that occurs in response to some stimulus. Although some studies did assess measures during a resting state, the majority of findings on over-arousal in relation to emotional aggression more accurately reflect psychophysiologic and emotional reactivity to a situation or stimulus. Second, arousal or reactivity are nonspecific terms that can refer to any psychophysiologic response system (e.g., electrodermal, cardiovascular, cortical, and so on). Responses from these systems typically do not correlate in the general population. Thus, it would be worthwhile for future studies to include more than one response system (as done by Raine et al) and see if the arousal/reactivity measures converge. If the measures converge, a general model of arousal or reactivity is supported. (ABSTRACT TRUNCATED)