Table 1. Demographic and Clinical Characteristics for the Total Sample and Subgroups According to Baseline Measures.
| Variable | Good sleepers (n = 1717) | Subsyndromal insomnia (n = 818) | Insomnia syndrome (n = 538) | Total sample (n = 3073) |
|---|---|---|---|---|
| Age, mean (SD), [range], y | 47.1 (15.1) [18-94] | 48.6 (15.1) [18-95] | 50.8 (14.3) [18-85] | 48.1 (15.0) [18-95] |
| Female, No. (%) | 987 (57.5) | 538 (65.8) | 385 (71.6) | 1910 (62.2) |
| Insomnia duration, mean (SD), y | NA | 4.6 (7.8) | 6.3 (9.3) | 5.2 (8.3) |
| ISI scorea | ||||
| Mean (SD), [range] | 4.6 (3.6) [0-16] | 10.4 (4.4) [0-23] | 15.1 (4.8) [0-28] | 8.0 (5.8) [0-28] |
| Clinical score ≥10, No. (%) | 187 (10.9) | 499 (61.1) | 467 (87.1) | 1153 (37.6) |
| Use of prescribed medication, No. (%) | 34 (2.0) | 118 (14.7) | 251 (47.2) | 403 (13.3) |
| Medical comorbidity, No. (%) | 1140 (66.4) | 630 (77.2) | 465 (86.4) | 2235 (72.8) |
| BDI score, mean (SD)b | 5.3 (5.4) | 9.6 (8.3) | 15.0 (10.6) | 8.1 (8.1) |
| STAI score, mean (SD)c | 33.3 (8.6) | 39.1 (10.5) | 44.4 (11.4) | 36.8 (10.5) |
| Clinically significant psychological distress, No. (%)d | 323 (19.0) | 289 (35.5) | 283 (52.8) | 895 (29.3) |
Abbreviations: BDI, Beck Depression Inventory; ISI, Insomnia Severity Index; STAI, State-Trait Anxiety Inventory.
a
Scores range from 0 to 28, with higher scores indicating more severe insomnia.
b
Scores range from 0 to 63, with higher scores indicating more severe depression.
c
Scores range from 20 to 80, with higher scores indicating more severe anxiety.
d
Measured by selected questions from the global sleep survey about depressive and anxiety symptoms in the previous 2 weeks.