NRG1 and major depressive disorder: Significant negative correlations between NRG1 mRNA isoform EGFα expression and depression severity score (r = −0.241, Praw = 0.045, PB-H = 0.270) as well as type III expression and positive symptom severity score (r = −0.377, Praw = 0.020, PB-H = 0.120) were observed but did not survive correction for multiple comparisons (Supplementary Table S6).