CASP1 and treatment resistant depression: We found that TRD eyes (n = 21) had significantly higher levels of NLRP3 (P < 0.0001), caspase-1 (P = 0.0182), IL-1β (P = 0.0007), and VEGF (P = 0.0011) and lower concentrations of 25 (OH) D (P < 0.0001).