MMP9 and psychotic disorder: Furthermore, we saw a positive association between MMP-9 activity and the left and right hippocampal FW in individuals with early phase psychosis (left: F(1, 39) = 7.91, p = 0.0091; B = 0.0015, Cohen’s d = 2.19; right: F(1, 39) = 6.68, p = 0.015; B = 0.0013, Cohen’s d = 4.11) but not in healthy individuals (Fig. 2, Supplementary Table 2).