Objectives
Depression may be a risk factor or a prodromal symptom of dementia, and decreased serum levels of brain‐derived neurotrophic factor (BDNF) have been observed in both depression and dementia. The aim of the present study was to determine whether serum levels of BDNF in the remitted or acute phase of depression predicted the transition from depression to dementia.
Methods
Serum levels of BDNF were measured in the acute phase of depression (n = 204) and after remission (n = 117), and we followed (mean: 24.3 months) the participants to assess the subsequent onset of dementia or mild cognitive impairment (MCI).
Results
Serum levels of BDNF after remission, but not those in the acute depressive phase, predicted the future development of dementia or MCI.
Conclusions
Patients with low serum BDNF levels, even after depression remission, might have an increased risk of developing dementia. These findings suggest a potential association between residual low serum BDNF levels after remission and the prodromal state of dementia, or the involvement of BDNF in the transition from depression to dementia. However, given that this study is low‐powered and preliminary, interpretation of the results should be approached with caution.