Behavioral and Psychological Symptoms of Dementia (BPSD), also referred to as neuropsychiatric symptoms, are highly prevalent across all types of dementia and represent a major clinical and societal challenge. These symptoms are associated with accelerated disease progression, reduced quality of life for people with dementia, and substantial burden for both formal and informal caregivers. In residential long-term care facilities, where BPSD are particularly common, management often relies heavily on psychotropic medication despite risks, including increased morbidity and mortality. International guidelines therefore recommend person-centered, non-pharmacological interventions as first-line treatment. However, existing non-pharmacological approaches show mixed effects, face implementation barriers, and often insufficiently account for individual differences such as premorbid personality, despite growing evidence that personality plays a key role in the development and severity of BPSD.
The Cognitive Model for Behavioral Interventions (CoMBI) is a person-centered, non-pharmacological intervention designed to address these limitations. CoMBI is grounded in the assumption that BPSD partly emerge when underlying core needs are insufficiently met. These core needs are shaped by premorbid personality characteristics and are activated by specific environmental triggers. Drawing on Beck's cognitive model of personality disorders and nursing interventions from the Nursing Intervention Classification, CoMBI distinguishes distinct personality profiles, each associated with characteristic unmet needs and triggering situations. For each profile, tailored intervention strategies have been developed to compensate for unmet needs by modifying environmental factors and caregiver responses.
The CoMBI training provides caregivers with a structured framework to understand BPSD in relation to premorbid personality and unmet core needs. Care staff are trained to assess BPSD, identify personality-related core needs and triggering events, and implement tailored interventions. This is well documented in a CoMBI care plan, specifying which interventions will be applied and the desired behavioral outcomes. The care plan can be reevaluated every care team meeting.
To empirically demonstrate the effectiveness of CoMBI, we will conduct a stepped-wedge cluster randomized trial (SW-CRT) with repeated measures. All units of the participating nursing homes will initially receive care as usual (CAU) and will sequentially transition to the CoMBI condition. Outcome measurements will be conducted every four weeks, including at the time each unit changes from CAU to CoMBI. Outcomes are assessed using the Neuropsychiatric Inventory Questionnaire (NPI-Q), the Global Deterioration Scale (GDS), Qualidem and the Montreal Cognitive Assessment (MoCA). To properly identify the core needs for CoMBI, two personality questionnaires will be administered, namely the Personality Inventory for DSM-5 Brief Form + Modified (PID-5-BF+M) and the Level of Personality Functioning Scale Brief Form 2.0 (LPFS-BF 2.0).
