Autism Spectrum Disorder (ASD) in adulthood remains underexplored relative to childhood-focused research, particularly in relation to lived experiences across diverse social environments. This study presents a qualitative, case-based inquiry into the life trajectory of a fully grown individual diagnosed with ASD, emphasizing adaptive processes, environmental interactions, and socio-functional outcomes. Grounded in a neurodiversity paradigm, the research integrates interpretive methodologies with structured analytical frameworks to investigate how social, infrastructural, and psychological variables shape everyday functioning.

The study employs a recursive, dialogic member-checking approach to enhance interpretive validity and participant-centered insight generation (Brear, 2019). Analytical procedures are informed by hybrid thematic coding methods, combining inductive and deductive strategies (Fereday & Muir-Cochrane, 2006). The inquiry situates findings within established classification systems such as the International Classification of Functioning (ICF), enabling structured comparison of functional domains (Cieza et al., 2005; Cieza et al., 2019).

Key findings reveal that adaptive functioning in adulthood with ASD is not solely determined by neurobiological constraints but is significantly mediated by environmental accessibility, societal perceptions, and institutional design. Social participation barriers, particularly in transportation systems and urban infrastructures, emerge as critical determinants of autonomy (Deka et al., 2016; Dirix et al., 2023). Furthermore, the study highlights the importance of individualized coping mechanisms, community support structures, and policy-level interventions in enhancing quality of life.

The results contribute to a nuanced understanding of ASD as a condition embedded within socio-environmental contexts rather than confined to clinical definitions. By bridging experiential narratives with empirical frameworks, this research advances theoretical and applied discussions on neurodiversity, accessibility, and adult-centered autism research. The implications extend to policy design, service provision, and interdisciplinary research aimed at fostering inclusive environments.

DOI: https://doi.org/10.5281/zenodo.19491146