The study examined fasting serum and plasma insulin and glucose levels and the HOMA-IR index in people with depression in an acute episode with and without psychiatric medications and in depression during remission, comparing them to the values in healthy controls. Random-effects between-group meta-analyses showed that insulin levels were increased in acute episodes of depression (g = 0.29, 95% CI 0.21–0.37, p < 0.001.) Similarly to insulin, the HOMA-IR index was increased during acute depression (g = 0.30, 95% CI 0.18–0.41, p < 0.001). Here, INS is linked to depressive disorder.