The Experience of Anxiety in Adolescents with Autism Spectrum Disorder 7The experience of anxiety in adolescents with Autism Spectrum DisorderThis thesis is comprised of three pieces ofworkfocusingon anxiety in children and adolescents with Autism SpectrumDisorder (ASD). The firstis an original piece of qualitative research, investigatingthe lived experience of anxiety in adolescents with ASD. Interpretative Phenomenological Analysis (IPA) revealed three main themes; “the impact of anxiety”, “managinganxiety” and “navigating relationships”. Participants reported core features of ASD both causing anxiety and protecting against it, highlightingthe complex interplay between the two. This led to the development of the literature review, which exploredthe overlap between ASD and Obsessive Compulsive Disorder (OCD).This review had three aims.Firstly, to outlinekey similarities and differences between ASD and OCD in youth. Secondly,evaluatingthe use of OCD-specific assessment for youth with ASD. Finally,OCD-specific treatment for youth with comorbid ASD and OCDand was reviewed. 15 studies were included in the review. The results suggested key differences between ASD and OCD,for examplein the overall number and type of obsessions and compulsions reported. In addition key differences in the function of behaviour,with obsessions viewed as intrusive in OCD and repetitive behaviour viewed as pleasure-seeking in ASD, were identified. Both the empirical paper and the literature review highlighted parents were crucial in supporting the young person with anxiety.This was also highlighted as a potential implication for clinical practice, in relation to post-diagnostic work and as an emphasis within treatment. The final discussion paper exploredcurrent guidance for clinicians on the facilitation of post-diagnostic supportand proposed suggestions for development in this area. In addition suggestions were made for clinicians to conduct thoroughand comprehensive assessments for anxiety, alongside ASD,to prevent comorbid anxiety disorders being misdiagnosed. To conclude my personal reflections on completing this research project are discussed.