Drug administration procedures
For each study, the drugs were prepared in an onsite pharmacy. Subjective drug effects were assessed throughout the session (see primary sources for each study’s time course and additional session timing details). The Blinded-Dose Purchase Task (described in more detail below) was administered at the end of the session so participants could experience the full time course of the drug prior to evaluating how many doses of the experienced drug they would purchase (approximately 2 h and 15 min following cocaine/placebo administration; approximately 7 h and 15 min following methamphetamine/placebo administration; and approximately 5 h and 15 min following completion of alcohol/placebo administration).