Salivary cortisol levels and challenging behavior in children with autism spectrum disorder § Sine ´ad Lydon a , Olive Healy a, *, Michelle Roche b,c , Rebecca Henry b,c , Teresa Mulhern d , Brian M. Hughes d a School of Psychology, Trinity College Dublin, Ireland b Physiology, School of Medicine, National University of Ireland, Galway, Ireland c NCBES Neuroscience Centre and Centre for Pain Research, National University of Ireland, Galway, Ireland d School of Psychology, National University of Ireland, Galway, Ireland Challenging behavior is behavior ‘‘of such intensity, frequency or duration that the physical safety of the person or others is likely to be placed in serious jeopardy, or behavior which is likely to seriously limit use of, or result in the person being denied access to, ordinary community facilities’’ (Emerson et al., 2001, p. 3). The prevalence of challenging behavior has been reported to be high among those with autism spectrum disorder (ASD); Murphy, Healy and Leader (2009) found that among a sample of 157 children with ASD, 82% of participants engaged in at least one form of challenging behavior while 32.5% of the sample engaged in self-injurious behavior (SIB), stereotypy, and aggression. Similarly, Jang, Dixon, Tarbox, and Granpeesheh (2011) found that among 84 children with ASD, 94% engaged in at least one form of challenging behavior including such forms as stereotypy, SIB, aggression, and property destruction. Predictors of challenging behavior include autism severity, cognitive functioning, language ability, level of adaptive functioning, and hyperactivity (Gabriels, Cuccaro, Hill, Ivers, & Goldson, 2005; Jang et al., 2011; McTiernan, Healy, Leader, & Mannion, 2011; Richards, Oliver, Nelson, & Moss, 2012). Research in Autism Spectrum Disorders 10 (2015) 78–92 A R T I C L E I N F O Article history: Received 13 September 2014 Received in revised form 21 October 2014 Accepted 23 October 2014 Available online 24 November 2014 Keywords: Autism Stress Cortisol Challenging behavior Stereotypy Repetitive behavior A B S T R A C T A relationship between stress and challenging behavior in individuals with autism spectrum disorder (ASD) has been theorized but infrequently examined empirically. The current study sought to examine the relationship between a parent-reported measure of stress, a physiological measure of stress (diurnal salivary cortisol), and various topographies of challenging behavior among 61 children and adolescents diagnosed with ASD between the ages of three and 18 years. Significant differences in cortisol levels between those engaging in high and low rates of stereotyped behavior were observed such that higher levels of stereotypy appeared an overt manifestation of higher levels of stress. A comparison between a subset of participants with ASD and typically developing peers matched on age, gender, and pubertal status failed to yield any differences in diurnal cortisol levels or cortisol variability between the two groups. The results of the current study suggest that similar levels of stress may exist among children with autism and their typically developing peers, but that for a subset of individuals with ASD, stereotyped behavior may be an indicator of elevated cortisol levels. ß 2014 Elsevier Ltd. All rights reserved. § This research was conducted at The National University of Ireland Galway and Trinity College Dublin and was supported by the Irish Research Council’s EMBARK Postgraduate Scholarship Scheme [RS/2012/134] and Science Foundation Ireland 11/RFP/NES/3175. * Corresponding author at: School of Psychology, Trinity College Dublin, College Green, Dublin 2, Ireland. Tel.: +353 1 896 1175; fax: +353 1 671 2006. E-mail address: olive.healy@tcd.ie (O. Healy). Contents lists available at ScienceDirect Research in Autism Spectrum Disorders Jo u rn al h om ep ag e: h ttp ://ees .elsevier .co m /RASD/d efau lt.as p http://dx.doi.org/10.1016/j.rasd.2014.10.020 1750-9467/ß 2014 Elsevier Ltd. All rights reserved.