Effects of gender, ETLE, and MAOA genotype were assessed using an ANOVA model with the AQ-PA score as the dependent variable. Statistical analysis revealed significant main effects of gender (F1,227 = 36.77, P<0.0001) and ETLE (F1,227 = 27.50, P<0.0001), but no main effect of MAOA genotype (F1,227 = 0.10, P = 0.75). As expected, physical aggression scores were higher among males and participants reporting exposure to early traumatic life events. The importance of MAOA genotype in modulating the impact of early trauma on adult physical aggression emerged when interaction effects were examined. We found significant MAOA×ETLE (F1,227 = 8.20, P = 0.005) and gender×MAOA×ETLE (F1,227 = 7.04, P = 0.009) interaction effects. The cumulative variance in the physical aggression score explained by the ANOVA effects involving the MAOA allele was 6.6%. Physical aggression scores were higher in men who had experienced early traumatic life events and who carried low MAOA activity alleles (Table 2 and Figure 1).
