In the logistic regression analyses used to investigate the duration of the transition from regular alcohol use to alcohol dependence as a function of the age of onset of alcohol dependence, genotype was not significant in any age range in both linear and quadratic models for duration. In the linear model for duration, modeled as log(1 + duration), Delta ERO values at Fz are signficant in the youngest age range, and both Fz and Cz ERO values are significant in the oldest age range. ERO results are consistent with those obtained in the DTSA models. Duration was significant in the three youngest age ranges. In the quadratic model for duration, modeled as the sum of log(1 + duration) and log(1 + duration)2, the Fz and Cz ERO values are significant only in the oldest age range. The effect of duration of drinking was significant in the three youngest age ranges with an overall U-shape in the two youngest age ranges. Since the beta value for the log(1 + duration) term is negative and the beta value for the log(1 +
