Analysis
A linear mixed model with restricted maximum likelihood estimation was used to examine the effects of condition (placebo, alcohol, methamphetamine, methamphetamine and alcohol), time and their interaction on neurocognitive and subjective outcomes. Using the likelihood-ratio statistic to determine the most parsimonious model, compound symmetry was considered best fit. Condition and time were entered into as the repeated factor, and separate models were built to examine each outcome. Where a main effect was observed, post-hoc paired t-tests with Bonferroni correction for multiple comparisons were conducted to examine condition and time differences. Considering the potential effect of sex differences in pharmacokinetics of alcohol and alcohol-induced dopamine release in healthy volunteers (