Presentation Master's thesis - Jonne Drost - Brain & Cognition Psychology

Depression has been increasingly recognized as a potential modifiable risk factor for dementia, although the nature of this association remains unclear. This study examined whether depression is associated with an increased risk of all-cause dementia, and whether this association differs by age of depression diagnosis and sex. A retrospective longitudinal cohort study was conducted using general practitioner records from the Academisch Netwerk Huisartsengeneeskunde Amsterdam UMC (ANHA) network, including 127,759 individuals aged 60 years and older. Depression and dementia were identified using International Classification of Primary Care (ICPC) and Anatomical Therapeutic Chemical (ATC) diagnostic codes. Cox proportional hazards regression analyses were performed, adjusting for demographic and cardiovascular covariates. Depression was associated with an increased risk of dementia (HR = 1.62, 95% CI [1.49, 1.75], p < .001). Both midlife (HR = 1.57, 95% CI [1.396, 1.769], p < .001) and late-life depression (HR = 1.67, 95% CI [1.502, 1.859], p < .001) were significantly associated with dementia, with a stronger effect observed for late-life depression. However, this association was no longer significant when excluding participants whose depression and dementia diagnoses were five or less years apart, suggesting a potential prodromal effect. Sex did not moderate the association. These findings suggest that depression, particularly in later life, is associated with an increased risk of dementia, although late-life depression may reflect a prodromal symptom of neurodegeneration. Future research should focus on disentangling causal mechanisms Additionally, these results can suggest that early identification and intervention of depressive symptoms may contribute to improved dementia prevention strategies.