The behavior of a 2½‑year‑old boy with a lack of social reciprocity and repetitive motor mannerisms is indicative of which disorder?

The behavior of a 2½-year-old boy exhibiting a lack of social reciprocity and repetitive motor mannerisms is most indicative of autism spectrum disorder (ASD). This disorder is characterized by challenges in social communication and interaction, along with restricted or repetitive patterns of behavior, interests, or activities. The lack of social reciprocity suggests difficulties in engaging with others, which is a core feature of ASD. Furthermore, the presence of repetitive motor mannerisms, such as hand-flapping, rocking, or other similar behaviors, further aligns with the diagnostic criteria for autism.

Social-pragmatic disorder focuses specifically on issues with the social aspects of communication but does not typically include the repetitive behaviors seen in autism. Generalized developmental delay encompasses a broader range of developmental concerns but does not specifically address the unique combination of social and behavioral symptoms characteristic of autism. Rett syndrome, while also associated with social and motor difficulties, typically occurs in females and includes distinctive regression in development, particularly in cognitive and motor skills, which may not be evident in the case described. Thus, the behaviors presented strongly point to autism spectrum disorder as the most accurate diagnosis.