Demographic and cocaine use characteristics of study participants (n = 12)
| Characteristic | Mean ± SD [range]* |
|---|---|
| Age, yr | 39.5 ± 8.0 [31–48] |
| Male sex, no. | 10 |
| Education, yr | 12.2 ± 0.9 |
| Employed, no. | 9 |
| Age at first use, yr | 23.7 ± 6.5 |
| Duration of use, yr | 15.9 ± 7.4 |
| Duration of dependence, yr | 11.6 ± 6.3 |
| Frequency (d/wk) | 4.3 ± 2.1 |
| Amount (g/wk) | 7.5 ± 4.5 |
| Primary route of administration, no. | |
| Smoked cocaine | 9 |
| Intranasal powder | 3 |
| Last use before PET scan 1, h | 448 ± 357 |
| Last use before PET scan 2, h | 174 ± 84 |
| Cigarette smokers, no. | 9 |
PET = positron emission tomography; SD = standard deviation.
↵* Unless indicated otherwise.