Table 2.
Sample characteristics based on age of onset of medical use of prescription stimulants (total across the 4 waves of the SSLS; n = 4755)
| Age of onset of medical use of prescription stimulants | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Contrast 1 | Contrast 2 | Contrast 3 | |||||||
| Never Used (n = 4433) % |
Early Onset (n = 150) % |
p(a) | Never Used (n = 4433) % |
Late Onset (n = 172) % |
p(a) | Early Onset (n = 150) % |
Late Onset (n = 172) % |
p(a) | |
| Gender | |||||||||
| Male | 48.3% | 66.0% | *** | 48.3% | 49.4% | 66.0% | 49.4% | ** | |
| Female | 51.7% | 34.0% | 51.7% | 50.6% | 34.0% | 50.6% | |||
| Race | |||||||||
| White | 61.0% | 80.7% | *** | 61.0% | 83.1% | *** | 80.7% | 83.1% | |
| Black | 33.1% | 16.0% | 33.1% | 13.4% | 16.0% | 13.4% | |||
| Other Race | 5.9% | 3.3% | 5.9% | 3.5% | 3.3% | 3.5% | |||
| Grade level | |||||||||
| 7th or 8th grade | 35.1% | 34.7% | 35.1% | 20.3% | *** | 34.7% | 20.3% | ** | |
| 9th or 10th grade | 31.9% | 25.3% | 31.9% | 41.9% | 25.3% | 41.9% | |||
| 11th or 12th grade | 33.0% | 40.0% | 33.0% | 37.8% | 40.0% | 37.8% | |||
| Parental education | |||||||||
| Parents have less than a college degree | 25.3% | 22.0% | 25.3% | 19.2% | 22.0% | 19.2% | |||
| At least one parent has a college degree or higher | 74.7% | 78.0% | 74.7% | 80.8% | 78.0% | 80.8% | |||
| YSR conduct disorder severity | |||||||||
| Conduct disorder severity (normal) | 89.3% | 79.3% | *** | 89.3% | 76.2% | *** | 79.3% | 76.2% | |
| Conduct disorder severity (borderline) | 4.7% | 10.0% | 4.7% | 11.0% | 10.0% | 11.0% | |||
| Conduct disorder severity (clinically significant) | 6.0% | 10.7% | 6.0% | 12.8% | 10.7% | 12.8% | |||
| ADHD diagnosis | |||||||||
| Never diagnosed with ADHD | 92.8% | 19.3% | *** | 92.8% | 30.8% | *** | 19.3% | 30.8% | * |
| Diagnosed with ADHD | 7.2% | 80.7% | 7.2% | 69.2% | 80.7% | 69.2% | |||
| YSR ADHD severity | |||||||||
| ADHD severity (normal) | 91.2% | 66.0% | *** | 91.2% | 68.0% | *** | 66.0% | 68.0% | |
| ADHD severity (borderline) | 6.0% | 18.0% | 6.0% | 21.5% | 18.0% | 21.5% | |||
| ADHD severity (clinically significant) | 2.8% | 16.0% | 2.8% | 10.5% | 16.0% | 10.5% | |||
| Past-year medical use of prescription stimulants | |||||||||
| Did not medically use prescription stimulants | 100.0% | 23.3% | *** | 100.0% | 26.7% | *** | 23.3% | 26.7% | |
| Medically used prescription stimulants | 0.0% | 76.7% | 0.0% | 73.3% | 76.7% | 73.3% | |||
| Past-year nonmedical use of prescription stimulants | |||||||||
| Did not nonmedically use prescription stimulants | 98.5% | 92.0% | *** | 98.5% | 92.4% | *** | 92.0% | 92.4% | |
| Nonmedically used prescribed stimulants | 1.5% | 8.0% | 1.5% | 7.6% | 8.0% | 7.6% | |||
| Onset of nonmedical use of prescription stimulants | |||||||||
| Never used stimulant medication nonmedically | 98.0% | 90.7% | *** | 98.0% | 87.2% | *** | 90.7% | 87.2% | |
| Early onset of nonmedical use | 0.6% | 7.3% | 0.6% | 5.8% | 7.3% | 5.8% | |||
| Late onset of nonmedical use | 1.4% | 2.0% | 1.4% | 7.0% | 2.0% | 7.0% | |||
| Past-year cigarette smoking | 10.4% | 24.0% | *** | 10.4% | 33.7% | *** | 24.0% | 33.7% | |
| Past-year binge drinking | 9.9% | 16.7% | ** | 9.9% | 26.7% | *** | 16.7% | 26.7% | * |
| Past-year marijuana use | 18.0% | 28.0% | ** | 18.0% | 41.3% | *** | 28.0% | 41.3% | * |
| Past-year cocaine use | .83% | 6.0% | *** | .83% | 4.1% | *** | 6.0% | 4.1% | |
| Past-year other illicit drug use | 3.4% | 13.3% | *** | 3.4% | 14.0% | *** | 13.3% | 14.0% | |
| Past-year other nonmedical prescription drug use | 10.6% | 17.3% | ** | 10.6% | 20.3% | *** | 17.3% | 20.3% | |
| Positive DAST-10 screen | 11.6% | 26.0% | *** | 11.6% | 33.7% | *** | 26.0% | 33.7% | |
| Positive CRAFFT screen | 17.6% | 26.7% | ** | 17.6% | 44.2% | *** | 26.7% | 44.2% | *** |
*
p<.05,
**
p<.01,
***
p<.001
(a)
Significance tests were based on Chi-square tests of independence (2×2 and 2×3). Results for 2×2 analyses were truncated, refer to table 1 for truncated groups.