Exploring psychological and cognitive processes as predictors and risk factors for prolonged grief disorder

Abstract

Although Prolonged Grief Disorder has now been formally recognised in ICD11 and DSM-5-TR, important conceptual and empirical questions remain. Ongoing debate concerns whether PGD is best understood as a distinct category or the severe end of a dimensional continuum, how grief severity relates to functional impairment, and which psychological and cognitive processes may help explain persistent distress following bereavement. These questions formed the basis of the present thesis.

This thesis examined the nature, correlates, measurement, and clinical significance of prolonged grief disorder across a programme of systematic review, psychometric evaluation, latent structure modelling, functional impairment analysis, and scale development. Taken together, the findings support a clear overall conclusion: PGD is best understood as a clinically significant, multidimensional, and biopsychosocial condition that varies primarily along a continuum of severity rather than existing as a clearly discrete category. Across the thesis, grief severity, comorbidity, somatic burden, and functional impairment increased in graded ways, while identity- and meaning-related processes, particularly the centrality of loss, appeared especially important in the persistence and impact of more severe prolonged grief.

The thesis first showed that prolonged grief extends beyond emotional pain alone. The first systematic review demonstrated consistent associations between PGD and poorer physical health, sleep disturbance, elevated physiological strain, and greater somatic symptom burden. This suggested that prolonged grief should not be viewed narrowly as an isolated emotional syndrome, but as part of a broader biopsychosocial burden. At the same time, the psychometric evaluation of the PHQ15 showed that somatic symptoms are themselves complex, with overlapping but distinguishable domains such as pain, cardiopulmonary symptoms, gastrointestinal symptoms, and fatigue. These findings indicated that somatic burden in grief is not a simple external correlate, but part of an interconnected distress system linking grief, mood, trauma-related processes, and bodily experience.

A major contribution of the thesis was to show that uncertainty in the disordered grief field is not only theoretical, but methodological. The second systematic review of pathological grief measures revealed striking heterogeneity in symptom coverage, diagnostic alignment, and analytic strategy. Across the literature, different instruments and modelling approaches often produced different conclusions about whether grief is unidimensional, multidimensional, or categorical. Much of this inconsistency appeared to reflect differences in measurement and method rather than genuine contradiction in the underlying phenomenon. The thesis therefore argued that stronger progress in the field depends on greater measurement harmonisation and the use of criteria-aligned instruments when testing competing structural models.

The empirical chapters then directly examined these structural questions using contemporary grief measures and advanced latent variable methods. The findings provided little support for a clean categorical model of PGD. Instead, the evidence suggested a dimensional backbone to pathological grief, with latent classes better understood as ordered severity strata than as natural categories. Even when class-based or factor mixture models were estimated, the identified groups appeared to reflect graded differences in symptom burden rather than qualitatively distinct syndromes. At the same time, certain symptoms, particularly blame and anger, seemed to become more prominent at higher levels of severity, suggesting that xxii some features of PGD may function as signposts of especially severe or clinically risky presentations rather than as stable core dimensions.

This dimensional interpretation was further strengthened by the functional impairment analyses. Across two ICD-11 aligned grief measures, impairment rose steadily as grief severity increased. The pattern was curved rather than strictly linear, with risk increasing sharply from low to moderate symptom levels and then tapering somewhat as impairment became more common at the upper end. Crucially, however, there was no evidence of a clear threshold or tipping point at which impairment suddenly emerged. Instead, impairment accumulated progressively across the severity continuum. Symptoms such as emotional numbness, difficulty accepting the loss, disengagement from activities, and anhedonia were most strongly linked to functional disruption, whereas yearning and preoccupation, although central to grief, were less predictive of impairment when examined individually. These findings suggested that diagnostic cut-offs are best understood as pragmatic decision points rather than markers of a natural boundary.

The final major contribution of the thesis was to move from structure to mechanism. The development and validation of the Centrality of Loss Scale showed that centrality of loss is a powerful and distinct correlate of prolonged grief severity. The findings suggested that grief may become especially persistent and impairing when the loss becomes a central organising feature of identity, meaning, and everyday life. Centrality of loss explained substantial variance in grief severity beyond traditional bereavement variables, indicating that how the loss is integrated into the self may matter more than many contextual risk factors alone. This helped integrate the entire thesis by showing that severe grief is not simply a matter of high symptom count, but reflects the cumulative interaction of emotional distress, bodily burden, functional disruption, comorbidity, and identity-related maintenance processes.

Overall, the thesis advances understanding of PGD by showing that it is best conceptualised as a multidimensional severity continuum embedded within a broader biopsychosocial network of distress and adaptation difficulties. Rather than asking whether pathological grief is categorically distinct from all other grief, the findings suggest that the more useful question is how severe, persistent, impairing, and identity-defining grief becomes, and what can be done to reduce that burden.

Date of Award	Jun 2026
Original language	English
Supervisor	Mark Shevlin (Supervisor) & Eoin McElroy (Supervisor)