Hill et al. (1999) predicted that the growth curves of their male participants at risk for alcoholism would converge with those of low-risk participants at age 22. In the present study, P300 amplitude of sons with high and low paternal risk differed significantly until age 20.87 years (although projected P300 values had not converged by this age or even by age 25; see Figure 3 and Figure 4a). The high- and intermediate-risk groups differed significantly between the ages of 17.63 and 20.15 years. This being the case, it is unclear why reductions are seen in abstinent adults with alcoholism as a function of familial risk at later ages (H. L. Cohen, Wang, Porjesz, & Begleiter, 1995; Patterson, Williams, McLean, Smith, Schaeffer, 1987; Pfefferbaum, Ford, White, & Mathalon, 1991; although see contrary findings in Glenn, Parsons, & Sinha, 1994, and Keenan, Freeman, & Harrell, 1997). Similarly, if the deviant trajectory is related to risk for antisocial personality disorder, it is unclear why P300 reductions are observed in adult antisocial men (e.g., L. O. Bauer, O’Connor, & Hesselbrock, 1994; Costa et al., 2000; O’Connor, Bauer, Tasman, & Hesselbrock, 1994).
