The purpose of the present investigation was to examine the association between circadian rhythms of cortisol and physical and relational aggression. Morning arrival, pre-lunch, and afternoon predeparture salivary cortisol were assessed among 418 maltreated and nonmaltreated children (52% maltreated; 49% female) attending a summer day camp. Counselors and peers rated participants' involvement in physically and relationally aggressive behaviors. Results indicated that physical aggression was associated with heightened cortisol following morning arrival and relatively steep declines in cortisol over the day whereas relational aggression was associated with low cortisol following morning arrival and blunted diurnal change in cortisol. Moreover, maltreatment was a significant moderator of this relationship such that aggression was related to greater cortisol dysregulation among nonmaltreated than maltreated children. The findings suggest that physiological correlates of aggression may differ for physical and relational forms of aggression and among maltreated versus nonmaltreated populations. Keywords aggression; gender; cortisol; maltreatment Involvement in aggressive and antisocial behavior is associated with a host of problems for children and adolescents, including rejection by peers, internalizing symptoms, and academic difficulties (e.g., Buhs, Ladd, & Herald, 2006;Crick, 1996;Farmer et al., 2003;Murray-Close, Ostrov, & Crick, 2007). Mounting evidence suggests that a number of biological processes, including resting heart rate, heart rate variability, blood pressure, and skin conductance are implicated in the development of aggressive and antisocial behavior (e.g., Kibler, Prosser, & Ma, 2004;Scarpa, Fikretoglu, & Luscher, 2000;Scarpa & Raine, 1997;Susman, 2006). Researchers have extended studies assessing biological underpinnings Correspondence regarding this article should be sent to Dianna Murray-Close, Psychology Department, 2 Colchester Avenue, Burlington, VT, 05405−0134 dmurrayc@uvm.edu.. Publisher's Disclaimer: The following manuscript is the final accepted manuscript. It has not been subjected to the final copyediting, fact-checking, and proofreading required for formal publication. It is not the definitive, publisher-authenticated version. The American Psychological Association and its Council of Editors disclaim any responsibility or liabilities for errors or omissions of this manuscript version, any version derived from this manuscript by NIH, or other third parties. The published version is available at http://www.apa.org/journals/dev/ NIH Public Access
Author ManuscriptDev Psychol. Author manuscript; available in PMC 2009 July 1.
Published in final edited form as:Dev Psychol. 2008 July ; 44(4): 1160-1176.
NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript of aggression to examine the role of the stress hormone cortisol (e.g., McBurnett, Lahey, Rathouz, & Loeber, 2000). However, existing research investigating the relation between cortisol and aggression is limited in...