There is a new publication in the Journal of Autism and Developmental Disorders co-authored by Sarah Barrett and Sue Leekam. The article describes the self-reported experience of anxiety and repetitive behaviour in young people aged 13-20 years from interviews and also questionnaires. The article is available by emailing the authors and will also be on open access in twelve months.
Joyce, C., Honey, E., Leekam, S. R., Barrett, S. L., & Rodgers, J. (2017). Anxiety, Intolerance of Uncertainty and Restricted and Repetitive Behaviour: Insights Directly from Young People with ASD. Journal of Autism and Developmental Disorders, 1-14.