Participants completed three randomized 4-hour study sessions, separated by at least 72 hours, during which they received placebo or d-amphetamine (10 or 20 mg) under double-blind conditions. They completed questionnaires measuring subjective effects before and 30, 60, 90, 150 and 180 minutes after ingesting the capsule; heart rate and blood pressure were also measured at these times; these procedures have been described previously [1] (also see Supporting Information S1). Subjective responses were measured using the Profile of Mood States (POMS) [33], the Drug Effects Questionnaire (DEQ) [34], and the Addiction Research Center Inventory (ARCI) [35], [36]. Thus, 22 phenotypes were obtained in four categories: 1) physiological: systolic and diastolic blood pressure, heart rate, 2) POMS scales: Friendliness, Anxiety, Depression, Fatigue, Anger, Elation, Confusion, Vigor, 3) DEQ scales: Feel Drug, Feel High, Want More, Like Drug, Dislike Drug, and 4) ARCI scales: Amphetamine, Benzedrine Group (BG), Marijuana, Lysergic Acid (LSD), Morphine-Benzedrine Group (MBG) and Pentobarbitol-Chlorpromazine-Alcohol Group (PCAG). Each of these 22 phenotypes was measured at six time points during three sessions (placebo, 10 and 20 mg), totaling 396 phenotypic values for
