Table 1. Clinical, behavioral characteristics, and brain volumes in community adolescents at age 16.
| Variable | Mean or % | SD | |
|---|---|---|---|
| Demographic variables | Age (years) | 16.83 | 0.61 |
| Sex | 55% (n = 56) female | ||
| Sleep variables (N = 101) | Wake up time WD | 7:03 | 0:43 |
| Wake up time WE | 10:01 | 1:15 | |
| Bed time WD | 22:42 | 0:43 | |
| Bed time WE | 00:05 | 1:10 | |
| WE delay wake up time | 2:59 | 1:17 | |
| WE delay bed time | 1:23 | 1:04 | |
| Time in bed WD | 8:18 | 0:59 | |
| Time in bed WE | 9:56 | 1:00 | |
| Sleep debt | 1:40 | 0:59 | |
| Performance scores (N = 82) | Delay discounting large amounts | -2.25 | 0.68 |
| Delay discounting medium amounts | -2.03 | 0.73 | |
| Delay discounting geomean | -2.06 | 0.66 | |
| Spatial working memory | 7.59 | 7.80 | |
| Behavioural problems (N = 74) | SDQ internalising | 4.34 | 2.40 |
| SDQ externalising | 7.36 | 2.68 | |
| Global brain measures (N = 101) | Total grey matter volume | 742.02 | 68.99 |
| Total white matter volume | 477.22 | 49.28 | |
| Total CSF | 395.55 | 40.89 | |
| Volume scaling factor | 1.32 | 148.21 |
WD = weekday; WE = weekend; CSF = cerebrospinal fluid; SDQ = Strenghts and Difficulties Questionnaire.