TABLE 4: The dynamics of plasma BDNF concentrations and main clinical characteristics in MNCD patients taking escitalopram.
Mild neurocognitive disorders (MNCDs) as an intermediate stage between normal cognitive aging and dementias, particularly Alzheimer's disease (AD), have recently become a subject of an increasing scientific interest .
According to recent epidemiological data, the overall prevalence of MNCDs among individuals older than 55 is 15.7%, with single-domain amnestic, multiple-domain amnestic, and nonamnestic subtype prevalence of 6.4%, 3.7%, and 5.6%, respectively .
The investigation of neurobiological aspects of MNCDs might shed light on some pathogenetic mechanisms, which could become targets for management of MNCDs.
Limited information is available for plasma/serum BDNF concentrations in patients with MNCDs. Although low levels of BDNF in serum  and plasma  were found in patients with MNCD-AD, no studies are available concerning BDNF levels in patients with ScVMNCD so far.
Hence, the purpose of our study was to evaluate plasma BDNF concentrations in patients with the main etiological types of MNCDs and to determine whether the assessment of plasma BDNF level could improve the diagnostics of MNCDAD and ScVMNCD.
Clinical studies and the evaluation of plasma BDNF concentrations were performed twice: at baseline in all enrolled persons and after 2 months of escitalopram treatment (daily dosage: 10 mg) in 20 patients with MNCDs. This dosage was prescribed in accordance with the FDA instruction for using the drug in elderly patients.
In this study, we found a decrease in plasma BDNF concentrations in patients with the main etiological types of MNCDs. The decrease was significant in patients with MNCD-AD and correlated with the severity of amnestic syndrome.
The ability of plasma BDNF level to discriminate patients with MNCD-AD makes it a candidate biomarker for early identification, monitoring, and intervention assessment in such an etiological type of MNCDs.