Behavioral and Biological Mechanisms of Social Functioning in Children with Autism Spectrum Disorder: A Randomized Clinical Trial for a Novel Intervention

Abstract

A child diagnosed with Autism Spectrum Disorder (ASD) shows significant difficulty with social interaction and social communication, which has profound consequences on their mental health, employment opportunities and quality of life. Various theories provide discussion for the etiology of these social and communication impairments, however further research is required to focus our understanding towards the most empirically supported theories. Therefore, the first aim of this dissertation was to evaluate which theories are supported by current empirical literature to explain the etiology of poor social functioning in children with ASD. The second aim of this dissertation was to investigate a promising new treatment to improve social functioning in young children with ASD. The first study in this dissertation investigated empirical support for nonverbal social skills widely believed to be important for healthy social functioning, namely, the capacity to identify faces and facial expressions, engage in joint attention, fixate on the eye region of faces and understand/use gestures during social interactions. A meta-analysis with fifteen studies in Chapter 2 demonstrated that these nonverbal social skills play a significant role in predicting healthy social functioning in children with ASD, an effect associated with a medium effect size. This relationship was independent of the type of nonverbal social skill and the participants’ age and gender, suggesting that the proposed nonverbal social skills play a significant role in social functioning throughout childhood and across both genders. A critical review of current behavioral and biological evidence in Chapter 3 identified that these nonverbal social skills may become impaired in children with ASD as a result of hyper-arousal and anxiety experienced during social situations. Additionally, the experience of anxiety was argued to have cascading effects on the development of secondary mechanisms that may impede social skills, such as perceptual difficulties with perceiving facial features as a whole and cognitive difficulties understanding the meaning of faces. Interestingly, Chapter 4 suggested that young children with ASD, who experience anxiety, as reported by parents, continue to attend to faces more than objects, as measured by eye tracking technology. Additionally, greater attention to faces compared to objects was not associated with social functioning in these children. These findings extend our understanding of social impairments in children with ASD by suggesting that the experience of anxiety may not reduce attention to faces. Intervention for these social impairments remains limited in young children with ASD, and therefore, a second aim of this dissertation was to explore a novel treatment. A critical review in Chapter 5 describes how the neuropeptide oxytocin regulates the capacity for social skills and the experience of hyper-arousal and anxiety. We argued that the greatest benefits of oxytocin treatment may occur during the younger years of life when neural systems are plastic and children are most sensitive to experience dependent growth. The safety and efficacy of oxytocin treatment in young children with ASD was investigated using a randomized placebo-controlled trial, presented in Chapter 6. Here, a five week course of oxytocin treatment was found to significantly improve parent rated social functioning in 31 children with ASD aged between 3 and 8 years. These findings were further supported by experimenter rated global improvements and parent observation ratings of improved eye contact. In summary, this dissertation contributes to the literature by refining current perspectives on the etiology of social impairments in ASD and demonstrating the therapeutic potential of oxytocin as a novel treatment for these impairments in young children with ASD.