Effect of block type and ADHD status on reaction time variability. NR = non-self-referential, SR = self-referential. For between-group analyses of reaction time variability (RTV), the control group was compared to the ADHD group when receiving placebo. The interaction between block type and ADHD status on reaction time variability (RTV) was significant, p < .03. In the control group, block type did not significantly impact RTV, p = .17. In the ADHD group when receiving placebo, RTV was significantly greater in the SR block compared to the NR block, p < .05