The difficulty begins with definition. People do not die the same way, and the field has long been split between two competing approaches. Time-based approaches assume dying unfolds within a standard window, an assumption embedded in health systems such as hospice eligibility, which in the United States is typically tied to a six-month prognosis. Disease-based approaches instead anchor the end of life to a terminal diagnosis. Both provide measurable timestamps, but both fail, the authors contend, because they ignore the psychological and subjective experience of dying. Prognoses are notoriously difficult to make and interpret, and research on end-of-life trajectories suggests the dying process can last anywhere from about 21 days to 25 years, a range that renders any fixed timeline arbitrary and risks denying people early palliative care, which studies have shown can improve quality of life, mood, and even survival.

The disease-based route has its own problems. Not every cause of death stems from a terminal illness, and what counts as terminal shifts with historical and medical context. Some cancers are treatable and manageable while others carry low survival rates; life-threatening illnesses such as AIDS can lead indirectly to death from other infections. Moreover, most older adults die not from a single mechanism but from a slow, gradual decline in health, functioning, and independence, meaning ordinary daily activities can cascade into death without any single diagnosable culprit. Because development is multidirectional, the authors argue, dying cannot be predicted reliably by one specific illness, and dying people continue to engage and function in society even as they die.

The SHiFT model offers a third way: a subjective, psychological definition. The authors define the end-of-life phase as the developmental period during which a person is aware that they are dying, with that awareness emerging from the intersection of three components embedded in a socio-historical context. The self shifts from the abstract recognition that everyone eventually dies to the personal reality that I am dying. Health shifts from a proactive pursuit, staying active to live a long life, to a reactive response, managing symptoms. Future-time shifts from an opportunity, hoping for a long life, to a necessity, preparing for the inevitable. Crucially, the model requires the presence, persistence, and magnification of all three components at once, and it treats the phase as dynamic: the intersection becomes more salient and increasingly overlaps as time passes.

The self component draws on a rich literature on identity and narrative. People build a sense of self that is temporal and chronologically integrated, co-authoring their past, present, and anticipated future with society. Dying disrupts this continuity. Qualitative work with people living with advanced cancer shows an iterative process of accepting, struggling, reconstructing life, and sharing the experience, with patients describing a new normality in which death becomes a matter of course. Researchers have called this double awareness, living until death, or holding onto life while dying. Because self-discontinuity is uncomfortable, associated with uncertainty, low self-esteem, and confusion, dying people often work to restore continuity with their past selves, insisting they are still themselves despite the illness, while others embrace the discontinuity, letting go of old worries and emotional habits as part of a new identity.

Health, the second component, is understood through the biopsychosocial model as encompassing biological, psychological, and social dimensions. The authors emphasize the subjective, lived experience of health, noting the robust association between self-reported health and mortality: people integrate family history, symptoms, and daily functioning into summative assessments that predict death surprisingly well. Objective evidence supports the subjective sense of decline. Studies of terminal decline show slow, steady deterioration followed by accelerated loss in motoric and cognitive functioning in roughly the last two years of life, and mobility research tracking more than 1,400 older adults found motor declines especially prominent in the final six months across terminal illness, organ failure, and frailty alike. Qualitative interviews echo these patterns, with dying people describing changing bodily signals, sudden downturns, and an intuitive sense that something was wrong even before diagnosis.

Declining health also brings losses of dignity, control, and autonomy, increased dependency, and, commonly, loneliness. Feeling like a burden emerges as a complex psychological state involving depending on others, witnessing the impact on caregivers, empathizing with them, and feeling responsible. Meta-syntheses of patients living with terminal cancer describe daily life revolving around treatment and dependence, accompanied by anxiety, guilt, helplessness, and losses of control, energy, dignity, and independence. Yet the picture is not uniformly bleak. Sharing the illness experience can buffer these negatives, and reconnecting with loved ones offers meaningful growth; some patients report feeling strong and well even amid decline, reflecting the multidirectional, multifaceted, and subjective nature of health in which gains and losses coexist.

The future-time component builds on socioemotional selectivity theory, which holds that people are always aware of lifetime as well as clock time, and that perceived time horizons, not chronological age, drive motivational shifts. When time feels limited, people pursue emotionally meaningful goals; when it feels expansive, they pursue knowledge-based goals. Strikingly, subjective closeness to death predicts objective mortality risk over 16 years even after controlling for health determinants, and subjective life expectancy tracks actual mortality. Dying people still think about the future, but in compressed, urgent terms: they avoid planning too far ahead, frame the future as a day-to-day endeavor to preserve control, and confront a new necessity of preparing for death, from wills and funerals to home and pet arrangements. The authors suggest dying people may develop a distinctive stance of savoring the time that remains, describing time as simultaneously important and meaningless.

The model is explicitly embedded in socio-historical context. Culture, race, socioeconomic status, and historical period define, constrain, and stretch the fabric of developmental change. Institutional supports at the end of life are unevenly distributed and accessed, shaping how dying people perceive themselves and how society views them, including discrimination against the dying. Cultural preferences vary widely: in the United States, individual autonomy in healthcare decisions can be a privilege shaped by racial and socioeconomic disparities, while in Japan end-of-life decisions may be collective, involving family or medical experts, with attendant tensions over being a burden. Modern medicine has simultaneously extended global life expectancy and lengthened the period spent dying, intensifying demands on care services and fueling public policy, legal, and bioethical debates about the very definition of death.

The authors are candid about limitations. The model centers on self-awareness, so people unaware of or in denial about dying, including infants, young children, and adults with severe cognitive impairment, fall outside the end-of-life phase as defined, even though environments around them change. Dying is a process, a lived experience, while death is a single point in time; someone who dies suddenly may never experience the world as a dying person. The phase itself is fluid: a person with dementia may weave in and out of it, a cancer patient in remission may exit it, and a centenarian may feel time constrained yet not perceive themselves as dying. The authors call for empirical tests comparing dying and non-dying people’s goals, behaviors, and perceptions, daily diary studies of fluctuating self-perception, and prospective studies asking when people recognized they were dying and how that awareness relates to actual change in functioning, so that the subjective inflection point of dying can finally be mapped onto its objective biology.

Subject of Research: A theoretical model defining the end-of-life phase as a developmental period based on awareness of self, health, and future time.

Article Title: The End-of-Life Phase as Part of the Lifespan: The Self, Health, Future-Time Model

Article References: M. Reynolds, C., & Grühn, D. (2026). The End-of-Life Phase as Part of the Lifespan: The Self, Health, Future-Time Model. Journal of Adult Development. https://doi.org/10.1007/s10804-026-09575-9

Image Credits: AI Generated

DOI: 10.1007/s10804-026-09575-9

Keywords: end of life, lifespan development, SHiFT model, dying, terminal decline, self-continuity, subjective health, future time perspective, socioemotional selectivity theory, palliative care, aging theory, End-of-Life