Decision-making involvement and quality of life in people with dementia: the mediating role of psychological needs

Decision-making involvement is important for maintaining a sense of self and quality of life in people with dementia. To date, few studies have explored the factors behind this relationship. We explored whether decision-making benefits quality of life by enabling fulfilment of basic psychological needs: autonomy, competence, and relatedness. We analysed one-year longitudinal data from 787 people recently diagnosed with dementia from the DETERMIND cohort. Path analysis examined cross-sectional and longitudinal associations between decision-making involvement and quality of life. Parallel mediation analysis tested whether psychological needs explained this relationship. Cognitive impairment was tested as a moderator of longitudinal associations. At baseline, decision-making involvement was positively associated with quality of life, fully mediated by satisfaction of all three psychological needs. Despite declines in cognitive function, decision-making involvement remained high and quality of life stable over one year. No significant longitudinal associations were found between decision-making involvement and quality of life. Decision-making involvement may support quality of life through psychological needs fulfilment. Stability in decision-making and quality of life suggests resilience among people with dementia in early stages. Supporting psychological needs through tailored interventions and decision-aid tools may have the potential to enhance quality of life as dementia progresses.