Objective: To analyse the prevalence of depressive symptoms in centenarians, identify their predictors, and explore the role of functional dependence as a contributing factor.

Design setting, and participants: Cross-sectional baseline data from the Swiss Centenarian Study (n = 102), including community-dwelling and institutionalised participants with complete data on depressive symptoms and functional capacity.

Measurements: Functional capacity was assessed using the Older Americans Resources and Services Multidimensional Functional Assessment Questionnaire. Depressive symptoms were measured with the Geriatric Depression Scale - Short Form. Group differences were analysed using Chi-squared tests; relationships were examined with correlations. Multiple linear regressions identified predictors. Mediation analysis explored the interplay between functional capacity, living situation, and depressive symptoms.

Results: Functional capacity varied, with basic activities of daily living generally better preserved than instrumental activities. Almost one-fourth of participants screened positive for possible clinical depression, which was significantly more common among institutionalised centenarians (p < .05). Health conditions, anxiety, and lower functional capacity were significant predictors of depressive symptoms and together explained 24.7 % of the variance, with anxiety being the strongest predictor followed by health conditions and functional capacity. Mediation analysis showed that functional capacity mediated the relationship between living situation and depressive symptoms, highlighting its critical role in mental health.

Conclusions: A significant proportion of centenarians screened positive for depression, underscoring the need for greater attention to depressive symptoms and systematic screening. Targeted interventions promoting functional independence may play an important role to prevent depression, and strategies are needed to encourage institutionalised very old individuals to re-develop and maintain a certain level of independence.