“…In one report, the authors found significantly lower VEGF levels in the peripheral blood of MDD patients than in healthy controls (Carvalho et al, 2013). However, other studies have reported no difference between the levels in peripheral blood of MDD patients and healthy controls (Dalby et al, 2013;Dome et al, 2009;Fornaro et al, 2013;Kotan et al, 2012;Ventriglia et al, 2009). These inconsistent findings may be due to many confounding factors, such as different study design, physical illness, age, gender distribution, medical history, length of illness, previous exposure to antidepressants, severity of depression, or sample source (plasma, serum, or whole blood).…”