Diagnosis can alter how a person explains the past, anticipates the future, understands the body, occupies social roles, and decides what aspects of illness should become visible to others. Yet identity change is often described as either biographical disruption or adaptation, leaving insufficient space for continuity, rejection, enrichment, ambivalence, recurrent rupture, and context-dependent reconstruction. This article develops a non-empirical theory that distinguishes the diagnostic event from the meaning assigned to it, illness identity from the wider self-concept, and intrapersonal change from relational negotiation. Engulfment, rejection, acceptance, and enrichment are treated as possible identity positions rather than ordered stages or fixed patient types. Disclosure, reflected appraisals, cultural expectations, embodiment, legitimacy, and access to relational or digital resources may redirect identity trajectories. Agency is conceptualized as constrained and relational rather than as an individual capacity to “accept” illness. Reconstruction is therefore recursive: accommodation can be followed by renewed disruption when symptoms, treatment demands, roles, or social responses change. The theory generates bounded, testable implications for healthcare engagement without assuming that a coherent illness identity is universally desirable or clinically beneficial.
