Group characteristics and substance use (n = 51)
| Measurement* | Control (n = 23) | User (n = 28) | t (χ2) | p value |
|---|---|---|---|---|
| Age, yr | 24.57 ± 3.55 | 25.54 ± 5.11 | 0.77 | 0.45 |
| Education, yr | 16.20 ± 2.28 | 15.95 ± 3.68 | 0.30 | 0.77 |
| Smokers, n | 19 | 26 | 1.09† | 0.30 |
| Nicotine use, yr | 7.21 ± 2.94 | 9.65 ± 5.75 | 1.68 | 0.10 |
| Cigarettes per day, n | 8.45 ± 5.34 | 9.51 ± 7.11 | 0.57 | 0.57 |
| Pack years | 3.04 ± 2.44 | 5.56 ± 6.33 | 1.63 | 0.11 |
| Age of first alcohol use, yr | 16.57 ± 1.85 | 15.98 ± 3.80 | 0.66 | 0.51 |
| Days per week with alcohol use, n | 1.24 ± 1.05 | 1.56 ± 1.35 | 0.90 | 0.37 |
| Units of alcohol per week, n | 6.31 ± 5.67 | 10.14 ± 9.01 | 1.70 | 0.10 |
| Fagerström Test for Nicotine Dependence, score | 1.00 ± 1.31 | 1.86 ± 2.22 | 1.63 | 0.11 |
| Age of first nicotine use, yr | 15.71 ± 1.74 | 14.96 ± 2.49 | 1.22 | 0.23 |
| Positive and Negative Affect Schedule, positive score | 21.17 ± 5.51 | 20.00 ± 6.43 | 0.69 | 0.49 |
| Positive and Negative Affect Schedule, negative score | 1.96 ± 3.14 | 1.29 ± 2.75 | 0.81 | 0.42 |
| Beck Depression Inventory II score | 6.09 ± 6.26 | 6.50 ± 4.42 | 0.28 | 0.78 |
| State Trait Anxiety Inventory, State score | 32.83 ± 5.69 | 31.71 ± 5.77 | 0.69 | 0.49 |
| State Trait Anxiety Inventory, Trait score | 35.48 ± 8.17 | 35.86 ± 7.71 | 0.17 | 0.87 |
| Age of first cannabis use, yr | 16.92 ± 2.57 | 15.68 ± 2.82 | 1.51 | 0.14 |
| Average frequency of cannabis use (last 12 mo, d/mo) | — | 23.61 ± 7.27 | — | — |
| Lifetime quantity of cannabis use, g | 1.29 ± 1.02 | 2309 ± 1655 | 7.38 | 0.001 |
| Participants with past ecstasy use, n | 3 | 18 | 10.71† | 0.001 |
| Occasions of ecstasy use, n | 2.33 ± 2.31 | 9.72 ± 2.19 | 2.88 | 0.01 |
| Participants with past cocaine use, n | 2 | 14 | 9.00† | 0.003 |
| Occasions of cocaine use, n | 5.50 ± 4.50 | 5.93 ± 2.73 | 0.08 | 0.94 |
| Participants with past amphetamine use, n | 4 | 18 | 8.91† | 0.003 |
| Occasions of amphetamine use, n | 3.25 ± 4.50 | 12.17 ± 15.39 | 1.13 | 0.27 |
| Participants with past hallucinogen use, n | — | 17 | — | — |
| Occasions of hallucinogen use, n | — | — | — | — |
| Participants with past opiate use, n | — | 3 | — | — |
| Occasions of opiate use, n | — | — | — | — |
| Participants with past solvents use, n | — | 7 | — | — |
| Occasions of solvents use, n | — | — | — | — |
| Post-experiment ratings | ||||
| Task enjoyment (scale of 1 to 9) | 6.09 ± 1.93 | 6.11 ± 1.99 | 0.04 | 0.97 |
| Performance self-evaluation (scale of 1 to 9) | 5.87 ± 1.33 | 5.18 ± 1.66 | 1.62 | 0.11 |