Performing basic activities of daily living (ADLs) is one of the major difficulties encountered in dementia, which can have considerable negative impacts on the quality of life (QoL) of people with dementia (PwD). However, the extent to which basic ADL performance deteriorates across mild, moderate, and severe dementia is little examined and its impact, together with depression and neuropsychiatric behavior, upon QoL, is of considerable relevance across European countries.