Grand mean event-related potential waveforms for each paternal risk group at each assessment are presented in Figure 2. Table 3 presents descriptive statistics for the observed values of P300 amplitude and age at each measurement for those differing in diagnostic status and paternal risk. In the growth model, P300 decreased significantly with age, F(1, 573) = 96.36, p <.001. There was a significant difference across paternal risk groups in the mean intercept, F(2, 187) = 3.77, p= .025, and slope, F(2, 573) = 3.59, p= .028, of the developmental trajectories. The P300 amplitude trajectories predicted by the model are presented in Figure 3. The paternal AAB group had a significantly different P300 amplitude trajectory from the low paternal risk group, χ2(1, N = 243) = 6.61, p= .010.2 The young men whose fathers had AAB had a trajectory characterized by a smaller intercept (M = 21.66 µV, SE = 1.07) and slope (M = −0.47 µV/year, SE = 0.13) than the low paternal risk group (mean intercept = 25.26 µV; SE = 1.31; mean slope = −0.86 µV/year, SE = 0.16).
