BDNF and depressive symptom measurement: There are some overlapping pathomechanism, that are present both in depression and neurodegenerative diseases like neuroinflammation [29] and the disturbances in monoamine neurotransmission [30], hypothalamus-pituitary-axis dysfunction, decreased levels of brain-derived neurotrophic factor (BDNF) and increased oxidative stress levels [29, 31].