Self-Report of Restricted Repetitive Behaviors in Autistic Adults: A Systematic Review.

Background: Autism research has relatively neglected restricted repetitive behaviors (RRB) and autistic adults compared with the social domain of autism and autistic children. With this review, we aimed to synthesize what is currently known about autistic adult's self-reported RRB, researcher's use of methods, and consideration of masking and gender, and to highlight gaps in our knowledge to inform future research. Methods: We conducted a systematic search of five databases that we last ran in February 2023. We included studies where autistic adults self-reported on one or more subtypes of their repetitive behaviors. We conducted a narrative synthesis to summarize results. We used the Mixed Methods Appraisal Tool to assess the quality of included studies. Results: Our database search identified 35 studies to include for review. The majority of included studies focused on the sensory domain of RRB with other subtypes comparatively neglected. The narrative synthesis identified subject areas of stimuli characteristics, internal reactions, moderators, recovery, self-regulation, and social pressure. We uncovered a narrative where most autistic adults experience hypersensitivity to some sensory stimuli, the unpleasantness of which they then try to avoid, but in doing so may also avoid social situations, contributing to loneliness and increased anxiety surrounding social situations. We identified a cycle of stress where existing stress increased sensory sensitivities leading to more stress and less ability to deal with additional stressors. While the self-regulatory benefits on emotion, cognition, and self-fulfillment of RRB should help with stress, this was prevented by autistic people's awareness of stigma surrounding these behaviors, leading to masking, which is also stressful. Conclusion: The review highlighted the need for a less categorical and more interrelated approach in researching this domain of autism and a need for more awareness surrounding sensory issues and the benefits of RRB. Future research should also strive to improve study sample representation, particularly regarding gender, race, and IQ. Community Brief: