Background and aimsPsychosocial factors may affect adherence to lifestyle interventions and lifestyle changes. The role of psychosocial factors in dementia prevention needs more research. We aimed at clarify the issue in the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER).MethodsThe population included 1260 participants aged 60–77 years at risk for cognitive decline, randomised to a multidomain lifestyle intervention or regular health advice for 2 years. Adherence was evaluated as participation in the provided activities and actual lifestyle changes, separately for each domain (diet, exercise, social/cognitive activity, vascular risk management) and combined into multidomain. Psychosocial factors were measured at trial baseline (depressive symptoms; study perception; health-related quality of life, HRQoL) and earlier life (hopelessness; satisfaction with family life, achievements, and financial situation).ResultsDepressive symptoms, hopelessness, and nonpositive study perception were negatively and HRQoL positively associated with participation in the multidomain intervention. Depressive symptoms, lower HRQoL, hopelessness and dissatisfaction with financial situation were associated with unhealthier lifestyles at baseline. Baseline depressive symptoms and lower HRQoL predicted less improvement in lifestyle, but did not modify the intervention effect on lifestyle change.Discussion and conclusionsSeveral psychosocial factors were associated with participation in lifestyle intervention, while fewer of them contributed to lifestyle changes. Although the intervention was beneficial for lifestyle changes independent of psychosocial factors, those most in need of lifestyle improvement were less likely to be active. Tailoring lifestyle-modifying strategies based on the need for psychosocial support may add efficacy in future trials.Trial RegistryClinicalTrials.gov NCT01041989 2010-01-05