Table 2.
Associations between smartphone-based sleep indices* and a self-reported sleep questionnaire†, and clinically rated depressive‡ and manic§ symptoms, respectively
| Model 1¶ | Model 2¶ | |||||
| B | 95% CI | P value | B | 95% CI | P value | |
| Smartphone-based self-reported hours slept between 12:00 and 06:00** | ||||||
| HAMD sleep item, n=471 | −0.10 | −0.15 to −0.05 | <0.001 | −0.10 | −0.15 to −0.05 | <0.001 |
| YMRS sleep item, n=471 | −0.30 | −0.43 to −0.17 | <0.001 | −0.30 | −0.43 to −0.17 | <0.001 |
| PSQI, n=383 | −0.08 | −0.11 to −0.05 | <0.001 | −0.07 | −0.10 to −0.05 | <0.001 |
| Smartphone-based self-reported daily variability in hours slept between 12:00 and 06:00†† | ||||||
| PSQI, n=248 | 0.05 | 0.02 to 0.08 | 0.001 | 0.05 | 0.02 to 0.08 | 0.001 |
| Automatically smartphone-generated hours slept between 12:00 and 06:00 | ||||||
| HAMD sleep item, n=136 | −0.03 | −0.10 to 0.045 | 0.46 | −0.02 | −0.094 to 0.05 | 0.57 |
| YMRS sleep item, n=136 | −0.08 | −0.25 to 0.07 | 0.29 | −0.08 | −0.25 to 0.08 | 0.31 |
| PSQI, n=115 | −0.002 | −0.037 to 0.33 | 0.92 | −0.003 | −0.038 to 0.033 | 0.89 |
| Automatically smartphone-generated daily variability in hours slept between 12:00 and 06:00 | ||||||
| PSQI, n=96 | −0.027 | −0.078 to 0.024 | 0.30 | −0.027 | −0.079 to 0.024 | 0.30 |
All participants are included in the analyses.
*Summary measures of smartphone-based sleep indices were calculated for the same time period as addressed by the self-reported and clinical rating scales: for the PSQI the past 28 days, and for the HAMD and YMRS the past 3 days.
†PSQI: total score.
‡HAMD: sum of items 4–6 addressing sleep.
§YMRS: subitem 4 addressing sleep.
¶Model 1: Unadjusted. Model 2: Adjusted for age and sex.
**Mean hours slept between 12:00 and 06:00.
††Daily variability in hours slept between 12:00 and 06:00 calculated for the past 14 days and 28 days, respectively, by using the RMSSD score.
Automatically smartphone-generated sleep between 12:00 and 06:00 calculated by using the screen on/off feature.
Daily variability in hours slept between 12:00 and 06:00 calculated based on screen on/off features and by using the RMSSD score.
HAMD, Hamilton Depression Rating Scale; PSQI, The Pittsburgh Sleep Quality Index; RMSSD, root mean successive difference; YMRS, The Young Mania Rating Scale.