Association between frailty and incidence of AMD among middle-aged and older people: evidence from the UK Biobank.

Pragmatic competence, the ability to use language appropriately in social contexts, is fundamental to human communication and to the development of social relationships across the lifespan (). Early systematic efforts to measure qualitative abnormalities in language use, distinct from structural linguistic deficits, were pioneered by Rapin and Allen () with their description of semantic-pragmatic disorder and later by Bishop () with the Children's Communication Checklist (CCC). These studies identified a heterogeneous group of children whose pragmatic difficulties overlap with, but are not fully explained by, diagnoses such as Autism Spectrum Disorder (ASD) or Developmental Language Disorder (DLD). Pragmatic competence is conventionally subdivided into several interrelated subdomains, each capturing a distinct aspect of language use in interaction. These typically include the contextual and discursive use of language, encompassing the production of relevant and coherent contributions; topic management and conversational repair; inferential comprehension, including the interpretation of presuppositions, implicatures, and non-literal language such as irony and figurative speech; the selection of speech acts appropriate to the social and communicative context; turn-taking and the regulation of communicative exchange; and the non-verbal aspects of communication such as prosody, gaze, and gesture (, ). The present review treats pragmatic language as a multidimensional construct that subsumes these subdomains, while recognising that included studies vary in the breadth and specificity with which they operationalise pragmatic ability. The introduction of Social (Pragmatic) Communication Disorder (SPCD) in the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5) () marked a significant development in the psychiatric classification of these impairments. SPCD was designed to categorize individuals with pragmatic deficits not attributable to ASD or structural language disorders. However, this new diagnosis intensified debates about the nosological boundaries between ASD, DLD, and pragmatic impairments (, ). Recent reviews acknowledge that SPCD presents distinctive clinical features and has potential utility as a diagnostic category (, ), while at the same time documenting persistent overlap with adjacent neurodevelopmental conditions, high comorbidity, and a paucity of SPCD-specific assessment tools (, ). Within this active debate, some authors emphasize the categorical specificity of SPCD as supported by the DSM-5, whereas others propose that pragmatic difficulties may be more parsimoniously conceptualized along a continuum spanning DLD, SPCD, and ASD (, ).