The GriefDiff study is a randomized controlled trial evaluating a differentiated, community-based model of grief support for older adults. It compares three intervention levels-Information and Grief Literacy (IGLiteracy), Individual Self-Help Program (ISelfHP), and Moderated Self-Help Groups (MSHGroups)-to assess their effectiveness in reducing prolonged grief and psychological distress. Participants are screened for risk of Prolonged Grief Disorder and relational needs, then randomized to matched or non-matched interventions. Outcomes are measured at baseline, post-intervention (3 months), and follow-up (6 months), focusing primarily on prolonged grief symptoms and secondarily on depression, anxiety, stress, attachment, social support, and traumatic stress. The study aims to provide evidence for a cost-effective, scalable, and preventive public health model of bereavement care.
Introduction Grief in later life is a common yet under-recognized public health issue. Although most older adults adapt to bereavement without formal intervention, a significant minority develop Prolonged Grief Disorder (PGD), characterized by persistent yearning, emotional pain, and functional impairment. Older adults are particularly vulnerable due to cumulative losses, declining health, social isolation, and reduced access to psychosocial resources. Despite the documented psychological, physical, and social consequences of adverse grief reactions, prevention and early intervention remain marginal in health and social care systems. Current responses to grief are often reactive and clinically oriented, focusing primarily on individuals who already present severe symptoms. This approach overlooks a large group of bereaved individuals experiencing substantial distress that does not yet meet diagnostic thresholds and limits opportunities for prevention. Furthermore, most existing interventions are hospital-based and individual-focused, while community-based and scalable approaches remain underdeveloped. In line with international policy frameworks, including the World Health Organization's stepped-care model for mental health, differentiated models of grief support propose that interventions should be matched to individuals' levels of need. Such models are typically organized as a pyramid, ranging from low-intensity informational support to more structured and specialized interventions. This approach aims to optimize resource allocation, increase accessibility, and promote equity in mental health care. Aims The primary objective of the GriefDiff study is to implement and evaluate the effectiveness of a differentiated, tiered model of grief intervention in reducing prolonged grief symptoms and psychological distress among older bereaved adults. Specifically, the study compares three intervention levels-IGLiteracy, ISelfHP, and MSHGroups-in terms of their impact on grief outcomes. A secondary objective is to test the added value of matching interventions to participants' risk levels and relational needs, examining whether matched allocations lead to superior outcomes compared to non-matched conditions. The study also aims to identify predictors of engagement and response to intervention, including attachment patterns, social support, and traumatic stress. Ultimately, this research seeks to inform public health strategies by providing evidence for a cost-effective, community-centred, and preventive model of bereavement care. Procedures Participants will be recruited through community and health organizations, including a national grief association and partner institutions. Individuals referred by these entities will undergo a screening process assessing eligibility, risk of PGD, and relational needs. Eligible participants will receive detailed information about the study and will provide written informed consent prior to participation. Data collection will follow strict ethical and confidentiality standards. All data will be anonymized and securely stored. Participants will be informed of their right to withdraw at any time without consequences. To promote retention and minimize attrition, several strategies will be implemented, including flexible scheduling, regular contact with the research team, reminders for assessment points, and the availability of both digital and non-digital intervention formats. A feedback mechanism will be established to allow participants to share their experiences and concerns throughout the study. All interventions will be delivered within a community-based framework and will be supported by standardized manuals and materials. Intervention providers will receive specific training and ongoing supervision to ensure fidelity and consistency across conditions. Trial Design The GriefDiff study is a rater-blinded, randomized controlled trial with three parallel intervention arms. Following baseline assessment, participants will be stratified according to risk of prolonged grief and relational needs and then randomized to one of the three intervention conditions: IGLiteracy, ISelfHP, or MSHGroups. Randomization will be conducted using block randomization within predefined risk-by-needs strata to ensure balanced allocation across conditions. Allocation concealment will be maintained through the use of a computer-generated random sequence, managed by an independent member of the research team. Outcome assessors will be blinded to participants' allocation. Participants will be assessed at baseline (T0), post-intervention at three months (T1), and follow-up at six months (T2). In addition to evaluating overall intervention effects, the design allows for the examination of matching effects by comparing outcomes between participants who were allocated to matched versus non-matched intervention conditions. This trial provides a rigorous methodological framework to test a differentiated, community-based model of grief care, with the potential to inform future service organization and policy in bereavement support.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
SINGLE
Enrollment
246
A low-intensity intervention with one group psychoeducation session on grief reactions and available support, followed by bi-weekly SMS reminders for three months. It represents the minimum active support.
A digital self-help program promoting emotional regulation and adaptive grief processing through psychoeducation and exercises. Participants complete activities over three months, supported by reminders and brief phone contacts. Printed materials are available if needed.
Weekly psychologist-led peer groups for three months, focusing on emotional expression, acceptance, meaning-making, and coping, using a standardized protocol.
InLuto Association
Lisbon, Portugal
Prolonged Grief Scale - Revised (PG13-R)
The PG-13-R is a 13-item self-report measure assessing Prolonged Grief Disorder symptoms according to DSM-5-TR criteria. Items are rated on a 5-point Likert scale (1 = not at all to 5 = several times a day/overwhelmingly).Total scores are calculated as the sum of all items. Total score range: 13-65. Higher scores indicate greater severity of prolonged grief symptoms. Diagnostic criteria include symptom duration (≥12 months) and functional impairment.
Time frame: Baseline (T0), Post-intervention at 3 months (T1), and Follow-up at 6 months (T2).
Depression, Anxiety and Stress Scales - Short Form (DASS-21)
The DASS-21 is a 21-item self-report questionnaire assessing depression, anxiety, and stress symptoms over the previous week. Each item is rated on a 4-point Likert scale (0 = did not apply to me at all; 3 = applied to me very much or most of the time). The measure consists of three subscales (Depression, Anxiety, and Stress), each comprising 7 items rated on a 4-point scale (0 to 3). Subscale scores are calculated as the sum of the 7 corresponding items. Score range (per subscale): 0 to 21. Higher scores indicate greater symptom severity in the respective domain.
Time frame: Baseline (T0), Post-intervention at 3 months (T1), and Follow-up at 6 months (T2)
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