Prevalence of prolonged grief disorder in adult bereavement: A systematic review and meta-analysis

Highlights

• Prolonged grief disorder (PGD) is expected to be included in ICD-11.

• A systematic literature search identified 14 eligible studies on PGD prevalence.

• Meta-analysis revealed a pooled prevalence of PGD of 9.8% (95% CI 6.8–14.0).

• A high level of heterogeneity and limited representativeness were found.

• Additional high-quality research using population-based designs is needed.

Abstract

Background

Prolonged grief disorder (PGD) is a bereavement-specific syndrome expected to be included in the forthcoming ICD-11. Defining the prevalence of PGD will have important nosological, clinical, and therapeutic implications. The present systematic review and meta-analysis aimed to estimate the prevalence rate of PGD in the adult bereaved population, identify possible moderators, and explore methodological quality of studies in this area.

Methods

A systematic literature search was conducted in PubMed, PsycINFO, Embase, Web of Science, and CINAHL. Studies with non-psychiatric, adult populations exposed to non-violent bereavement were included and subjected to meta-analytic evaluation.

Results

Fourteen eligible studies were identified. Meta-analysis revealed a pooled prevalence of PGD of 9.8% (95% CI 6.8–14.0). Moderation analyses showed higher mean age to be associated with higher prevalence of PGD. Study quality was characterized by low risk of internal validity bias but high risk of external validity bias.

Limitations

The available studies are methodologically heterogeneous. Among the limitations are that only half the studies used registry-based probability sampling methods (50.0%) and few studies analyzed non-responders (14.3%).

Conclusions

This first systematic review and meta-analysis of the prevalence of PGD suggests that one out of ten bereaved adults is at risk for PGD. To allocate economic and professional resources most effectively, this result underscores the importance of identifying and offer treatment to those bereaved individuals in greatest need. Due to heterogeneity and limited representativeness, the findings should be interpreted cautiously and additional high-quality epidemiological research using population-based designs is needed.

Introduction

The psychological and physiological reactions that follow the loss of a loved one are collectively known as grief. Most individuals go through a painful, but natural, grieving process where the intensity of grief-related distress typically decreases gradually over time (Jordan and Litz, 2014). Thus, although bereavement can be a highly stressful and significant life experience, most individuals have sufficient internal resources and external support to adequately cope with their grief and slowly readjust to a life without the deceased (Prigerson et al., 2009, Zisook and Shear, 2009). However, research has also shown that for a significant minority of bereaved individuals the grieving process is particularly complicated (e.g., Lichtenthal et al., 2011; Prigerson et al., 2009; Simon et al., 2007). Instead of a decreasing intensity of grief-related distress, these individuals experience severe grief reactions that become abnormally persistent and increasingly debilitating across time (Jordan and Litz, 2014, Maercker et al., 2013, Prigerson et al., 2009).

Prolonged grief disorder (PGD) is a proposed diagnostic category intended to classify bereaved individuals who experience notable dysfunction for atypically long periods of time following a significant loss (Prigerson et al., 2009). Core symptoms include a pervasive yearning for the deceased or persistent preoccupation with the deceased accompanied by intense emotional pain (World Health Organization, 2016). Furthermore, PGD is characterized by difficulties in engaging in social or enjoyable activities, a reduced ability to experience positive mood, and difficulties accepting the death of the loved one (World Health Organization, 2016). A duration criteria of six months is proposed to ensure that natural grief reactions in the acute state following bereavement are not confounded with the syndrome of PGD (Prigerson et al., 2009). Research have found symptoms of PGD to be associated with impairment of the bereaved person's familial, social, and occupational functioning to a similar extent as found for other mental disorders, e.g., depression and post-traumatic stress disorder (Jordan and Litz, 2014, Maercker et al., 2013, Prigerson et al., 2009, Shah and Meeks, 2012).

The identification of PGD fostered the issue of whether to include the condition as an official mental disorder in the diagnostic manuals. In relation to recent revisions of both the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5; American Psychiatric Association, 2013) and the International Classification of Diseases (11th ed.; ICD-11; World Health Organization, 2016), working groups were established to investigate the validity, specificity, and treatability of PGD. While the group editing DSM-5 initially embraced the possibility of including PGD as a mental disorder, the proposal was finally rejected in 2013 (Bryant, 2014, Rosner, 2015). However, a code diagnostically corresponding to prolonged grief problems – Persistent Complex Bereavement Disorder (PCBD) – was added in the Appendix as a candidate disorder demanding further study (American Psychiatric Association, 2013, Maciejewski et al., 2016). Currently, PGD remains proposed for inclusion in the forthcoming ICD-11, scheduled for release in 2018 (World Health Organization, 2016). Inclusion of PGD will initiate the application of the diagnosis in healthcare settings. However, a number of unanswered questions remain regarding the impact of PGD, including the prevalence of the disorder in the general population. To date, systematic reviews of PGD have addressed its predictors, its prevention, and the effect of interventions to reduce grief-related symptoms (e.g., Lobb et al., 2010; Rosner et al., 2010; Wittouck et al., 2011). So far, only a limited number of epidemiological studies have assessed the prevalence of PGD in general population samples, and, to the best of our knowledge, no systematic reviews combining and comparing the existing individual studies of PGD prevalence have yet been published.

With no clear-cut data regarding the prevalence of PGD, much published theory and research use rather arbitrary expressions, such as “a significant minority” (e.g., Jordan and Litz, 2014; Zisook et al., 2010), to describe the number of individuals experiencing severe complications following bereavement. However, healthcare services are in need of a more precise estimate of the prevalence of PGD in the general population. Preferably, this information should be provided before the diagnosis is introduced to allocate economic and professional resources most effectively. We therefore conducted a systematic review and meta-analysis with the aim of providing an estimate of the prevalence of PGD in the general adult bereaved population.