IGF1 and major depressive disorder: The results showed that the baseline IGF-1 levels were significantly higher in MDD patients compared to the control group (p < 0.0001), while IGF-1 levels in the subsequent measurement (T1) in the MDD group were significantly lower than before the treatment (p < 0.0001) and not significantly different from HC (F = 1.86, p = 0.18).