Psychiatric or psychological treatment of depression in older adults and subsequent risk of dementia: Health and Retirement Study2012-2020.

Depression is an established risk factor for dementia. However, it is unclear whether initiating psychiatric/psychological treatment of depression, particularly early initiation of such treatment, may reduce risk of dementia. We examined associations between initiation and immediate initiation of psychiatric/psychological treatment and subsequent risk of dementia in older adults. Participants aged ≥60 years from the Health and Retirement Study from 2012 to 2018 with self-reported newly diagnosed depression but no history of dementia were included and followed up through 2020. Two sets of analyses were performed to examine initiation and immediate initiation of psychiatric/psychological treatment in relation to subsequent risk of dementia. Logistic regression models with stabilized inverse probability of treatment and censoring weights were used to estimate cumulative incidence and risk ratios (RRs), and 95% confidence intervals (CIs) were calculated using 500 sets of bootstrapping. In analyses of 2269 non-unique participants with self-reported newly diagnosed depression, initiation of psychiatric/psychological treatment anytime after diagnosis showed no risk reduction of dementia. However, in other analyses of 1257 unique participants with self-reported newly diagnosed depression, immediate initiation of psychiatric/psychological treatment was associated with a lower risk of dementia across 8 years of follow-up (RR = 0.64, 95% CI: 0.37, 0.96). Therefore, timely initiation of psychiatric/psychological treatment may reduce the risk of subsequent dementia among older adults with newly diagnosed depression. These findings further emphasize the importance of early treatment in managing late-life depression.