Table 1.
Demographic information and questionnaire scores for the healthy control and DSWPD groups
| Control | DSWPD | P | |
|---|---|---|---|
| Age (years) | 22.36 (3.26) | 20.80 (2.35) | 0.23 |
| Body mass index (kg m−2) | 22.62 (2.45) | 22.22 (4.19) | 0.79 |
| Bedtime | 23:23 (00:49) | 3:10 (01:13) | <0.001 |
| At‐home DLMO time | 20:50 (00.17) | 01:05 (01.24) | <0.001 |
| Phase angle (h) | 2.45 (0.73) | 1.49 (1.53) | 0.09 |
| Morningness–Eveningness Questionnaire | 56.64 (4.30) | 39.00 (4.72) | <0.001 |
| Pittsburgh Sleep Quality Index (range = 0–12) | 2.40 (1.51) | 7.22 (2.54) | <0.001 |
| Insomnia Severity Index (0–18) | 1.55 (1.51) | 12.33 (3.28) | <0.001 |
| Beck Depression Inventory – II (0–11) | 1.09 (1.14) | 6.00 (3.00) | <0.001 |
| DASS‐Depression (0–7) | 0.80 (0.63) | 4.25 (2.38) | <0.001 |
| DASS‐Anxiety (0–4) | 0.40 (0.70) | 1.63 (1.30) | 0.02 |
| DASS‐Stress (0–11) | 1.20 (1.99) | 4.88 (3.44) | 0.01 |
| General Anxiety Disorder 7‐item scale (0–10) | 0.80 (1.48) | 4.50 (2.78) | 0.002 |
Data are presented as mean and SD. Times are given as hours and minutes. Average bedtime was determined using the pre‐lab actigraphy. Dim light melatonin onset (DLMO) was measured using a 4 pg/ml cutoff (Carskadon et al. 1998). Phase angle is the time difference (h) between DLMO and actual bedtime (not desired bedtime). DASS, Depression, Anxiety and Stress Scale.