Date of Graduation

12-2014

Document Type

Dissertation (PhD)

Program Affiliation

Neuroscience

Degree Name

Doctor of Philosophy (PhD)

Advisor/Committee Chair

Scott D. Lane, Ph.D.

Committee Member

Anne B. Sereno, Ph.D.

Committee Member

Richard A. Meisch, M.D., Ph.D.

Committee Member

Anthony A. Wright, Ph.D.

Committee Member

Kevin A. Morano, Ph.D.

Abstract

EFFECTS OF OXYTOCIN ON HUMAN AGGRESSION

Joseph Louis Alcorn III, B.S.

Advisory Professor: Scott D. Lane, Ph.D.

Human interaction is comprised of common, yet complex, behaviors and the outcomes of these social behaviors can beneficially or detrimentally impact individual and public health. One social behavior that can have profound detrimental outcomes is aggression. Aggression is a class of social behavior that is particularly prevalent in individuals with antisocial personality disorder (ASPD) and comorbid substance use disorder (SUD). Aggression in these individuals can manifest at maladaptive levels that place considerable burdens on public health and communities. Therefore, understanding the neurobehavioral underpinnings of aggression holds substantial merit. The goal of this project was to examine the effects of this oxytocin (OT) on human aggression. Considerable work has demonstrated that OT engenders the promotion of affiliative social behaviors that are mutually beneficial (or prosocial) between two individuals. Aggression is characterized, in part, by social behaviors that are antisocial (which are opposite to prosocial behavior). The hypothesis was that acute administration of OT would reduce the frequency of human aggression. This hypothesis was tested in both individuals with comorbid ASPD and SUD, and healthy volunteers.

This project employed a well-established laboratory measure of human aggression, the Point Subtraction Aggression Paradigm, which measures changes in the frequency of aggressive behavior. In ASPD+SUD individuals there was no significant reduction in aggressive behavior following OT administration. However, there were non-systematic individual differences on aggressive behavior following OT dosing, which suggested modulation of aggressive behavior by OT. In healthy volunteers there was no significant effect of OT dose on aggressive behavior. However, in healthy volunteers, an examination of individual differences focused on antisocial personality traits revealed that aggressive behavior under OT was positively correlated with interpersonal manipulation and anger (Pearson’s r = 0.57). Healthy volunteers with higher scores of interpersonal manipulation and anger actually showed an increase in their aggressive behavior following OT administration.

In both ASPD+SUD individual and healthy volunteers, the hypothesis that OT would decrease human aggression was not supported. The experiments of this dissertation revealed substantial individual differences in aggression following OT administration, which is important for future research in examining the therapeutic efficacy of OT for the management of aggression in antisocial and substance abuse populations.

Keywords

oxytocin, aggression, social behavior, antisocial personality disorder, substance use disorder, individual differences

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