Table 3 Comparison of Cys C serum concentrations (mg/L) in MDD patients with different clinical picture of depressive episodes

Male (n = 49)

0.90 (0.81–0.98)

Z = −4.052

Female (n = 81)

0.80 (0.73–0.90)

With family history of depression (n = 15)

0.85 ± 0.11

t = 0.019

Without family history of depression (n = 115)

0.85 ± 0.12

With traumatic life events (n = 12)

0.94 (0.88–0.98)

Z = − 3.014

Without traumatic life events (n = 118)

0.82 (0.75–0.92)

With first-episode depression (n = 78)

0.83 (0.76–0.93)

Z = − 0.525

With recurrent depression (n = 52)

0.84 (0.75–0.96)

With suicidal ideation (n = 89)

0.86 ± 0.12

t = − 3.332

Without suicidal ideation (n = 41)

0.79 ± 0.11