Research progress on developmental characteristics and clinical intervention of restricted and repetitive interests/behaviors in autism spectrum disorder across the lifespan: a narrative review

Restricted and repetitive interests/behaviors (RRBs) are a core symptom domain of autism spectrum disorder (ASD), with a significant impact on social interaction, learning, and overall functioning of autistic individuals. Clinical features of RRBs in ASD encompass repetitive sensorimotor (RSM) behaviors and insistence on sameness (IS). Taking a lifespan approach, this narrative review synthesizes current understanding of the neurobiological and psychological mechanisms associated with RRBs, together with their clinical manifestations during each developmental phase, and discusses recent advances in clinical interventions. Importantly, the available evidence is not distributed evenly across the lifespan: RRBs have been studied far more extensively in early childhood, whereas evidence concerning middle-aged and older autistic adults remains very limited. This review therefore does not imply that the evidence base is equally strong at every life stage. It aims to provide a practical clinical reference for professionals in pediatrics, rehabilitation medicine, and related fields.