We conducted polygenic risk score (PRS) analyses to explore the relationship between genetic risk of SCZ and DEPR, and BD subtypes and psychosis (Figure 2, Supplementary Table 13). PRS calculated from SCZ 31 were significantly higher in BD1 cases than in BD2 cases (p=5.6×10−17, P threshold = 0.1) and in cases with psychosis compared to those without psychosis (p=2.12×10−6, P threshold =0.1). Conversely, PRS calculated from DEPR 33 were significantly higher in BD2 cases than in BD1 cases (P=8.5×10−10, P threshold = 0.01), independent of psychosis. Genetic correlations from LD-score regression support these results; genetic correlations were greater for SCZ with BD1 (rg = 0.71, se = 0.025) than with BD2 (rg = 0.51, se = 0.072), and were greater for DEPR with BD2 (rg = 0.69, se = 0.093) than with BD1 (rg = 0.30, se = 0.028) (Supplementary Table 12).
