A Systematic Review of Systematic Reviews and Meta-Analyses of Complicated Grief

Background and Purpose: Complicated grief (CG) is a prolonged grief syndrome distinct from other psychological bereavement reactions. CG is associated with significant mental and physical health complications beyond the risks of uncomplicated grief. Although emerging evidence supports the existence of this unique disorder, there remains considerable disagreement among researchers regarding its conceptualization. CG is listed in the appendix of the Diagnostic and Statistical Manual of Mental Disorders-5 (2013) as an area in need of further study, and CG criteria have been proposed for inclusion in the eleventh edition of the World Health Organization’s International Classification of Diseases. Numerous systematic reviews and meta-analyses have evaluated existing CG research. The purpose of this overview was to provide a comprehensive summary of findings pertaining to the epidemiology, etiology, measurement, correlates, and treatment of CG.

Methods: A systematic literature search of nine computerized bibliographic databases and two gray literature databases was conducted. A comprehensive search string comprising all known synonyms of CG was identified in the grief literature, and keywords indicating that the papers published were systematic reviews or meta-analyses published between 2000 and 2017 was employed. Inclusion/exclusion criteria were established prior to the bibliographic search and data extraction efforts were used to identify systematic reviews and meta-analyses related to CG. Title and abstract screening, full-text reviews, and data extraction were performed in duplicate. Disagreements were resolved through mutual discussion. Twenty systematic reviews/meta-analyses were identified for inclusion through this search as well as hand searches of included studies. Quality was assessed using a modified AMSTAR-2 assessment.

Results: This is the first systematic review of systematic reviews and meta-analyses of CG. Seventeen systematic reviews and three meta-analyses were identified. Most studies were of low or moderate quality, with only two receiving a high-quality rating. The majority of study samples were comprised of older, highly educated, Caucasian women of high socioeconomic status. There was significant diversity in diagnostic criteria, terminology, screening, and assessment tools used to identify CG. Correlates of CG included posttraumatic stress disorder, depression, and anxiety-related disorders. Predictors of CG included female sex, race/ethnicity, and lower socioeconomic status, having lost a child or spouse, and cancer as cause of death. Prevalence of CG was found to be, on average, 6% in the general population, and as high as 20% in specialized populations (e.g. carers of dementia patients).  Methodological issues included small sample sizes and diversity in assessment tools that limited the generalizability of study findings. Eleven screening tools for CG were identified employing diverse definitions and cutoffs to differentiate normal and CG. The use of targeted treatment rather than preventative interventions was supported by the findings of this overview with moderate-to-large effect sizes.

Conclusions and Implications Future research should explore CG among individuals of more diverse racial and ethnic identities and socioeconomic backgrounds, as the populations primarily studied were homogenous. The variation in basic terminology, diagnostic criteria, and assessment tools has limited empirical research of this disorder. Consensus regarding these areas is needed to promote the identification and treatment of this disorder.