Participant and scan characteristics
| Characteristic | Placebo | Amph | p value |
|---|---|---|---|
| Participants (male), n | 9 (2) | 10 (3) | — |
| Age, yr | 23.6 ± 4.0 | 24.6 ± 4.5 | 0.60 |
| TPQ novelty-seeking score | 25.2 ± 3.1 | 22.0 ± 3.1 | 0.04 |
| Lifetime stimulant drug use, n | 0.67 ± 1.1 | 0 ± 0 | 0.11 |
| Scan characteristics | |||
| Days between scans, n | 22 ± 2.7 | 23 ± 3.2 | 0.32 |
| Mass ligand injected PET 1, ng/kg | 182 ± 149 | 105 ± 63.9 | 0.16 |
| Mass ligand injected PET 2, ng/kg | 268 ± 282 | 127 ± 102 | 0.73 |
| (E)-isomer PET 1, % | 91 ± 5.3 | 93 ± 2.4 | 0.44 |
| (E)-isomer PET 2, % | 92 ± 4.3 | 92 ± 3.0 | 0.91 |
Amph = dextroamphetamine; PET = positron emission tomography; TPQ = Tridimensional Personality Questionnaire Unless otherwise indicated, values are mean ± standard deviation; p values from independent-samples t tests (Amph group versus placebo group).