Time course of effects of GHB (left panels) and ethanol (right panels) on DEQ participant ratings of drug effect, circular lights score, SEQ participant ratings of good effect and bad effects, and SEQ participant ratings of headache. Ordinates show participant ratings, with the exception of circular lights, for which the ordinates show score. Abscissas show time after drug administration in hours. Data points show least-squares adjusted means. Filled symbols indicate values that are significantly different from the corresponding placebo value at the same time point (planned comparisons).