BDNF and depressive symptom measurement: The findings make an important contribution to this expanding field of VEGF research, which can be emphasized as follows: even though BDNF is currently the most studied neurotrophic factor in neurobiology in MDD, the effects of VEGF on the pathogenesis of depression should not be underestimated, which means that the relationship between VEGF and depression should be investigated thoroughly; the correlation between VEGF and depression remains inconsistent, so the effect of VEGF on depression should be designed to combine with environmental variables.