Comparisons between participants with and without insomnia symptoms and preliminary evidence of efficacy of CBT-I based on daily diary data and questionnaires
| No insomnia (N=10)* Mean (SE) | Pre-CBT-I (N=10) Mean (SE) | Insomnia vs no insomnia t test and effect size (95% CI) | Immediately post-CBT-I (N=10)†‡ | Insomnia pretreatment vs post-treatment T test and effect size (95% CI) | 1 month follow-up (N=8)§ Mean (SE) | Insomnia pretreatment vs follow-up T test and effect size (95% CI) | |
| Primary CBT-I outcomes | |||||||
| Sleep-onset latency in minutes | 12.52 (2.80) | 47.40 (9.02) | t(16)=3.34, p=0.004; 1.51 (.47 to 2.52) | 17.11 (3.93) | t(9)=3.95, p=0.003; 1.25 (.39 to 2.07) | 23.03 (7.60) | t(7)=2.33, p=0.05; .82 (−0.01 to 1.53) |
| Wake after sleep onset in minutes | 16.35 (5.19) | 36.41 (3.12) | t(16)=3.46, p=0.003; 1.56 (.51 to 2.58) | 17.68 (4.75) | t(9)=3.86, p=0.004; 1.17 (.36 to 1.95) | 21.14 (5.55) | t(7)=2.92, p=0.02; .98 (.13 to 1.78) |
| Hours of sleep | 7.30 (.12) | 7.21 (.78) | t(16)=-.09, p=0.93; −0.04 (−0.93-.89) | 7.52 (.22) | t(9)=-.37, p=0.72; −0.11 (−0.70-.49) | 7.27 (.18) | t(7)=-.71, p=0.50; −0.24 (−0.89-.44) |
| Sleep efficiency (%) | 89.62% (1.0) | 75.20% (4.76) | t(16)=−2.66, p=0.017; 1.20 (.21 to 2.16) | 91.51% (1.34) | t(9)=−3.77, p=0.004; 1.14 (.34 to 1.91) | 89.62% (2.23) | t(7)=2.71, p=0.03; .90 (.08 to 1.69) |
| Insomnia Severity Index | 5.40 (.64) | 16.50 (1.68) | t(18)=6.17, p<0.001; 2.64 (1.43 to 3.83) | 4.38 (.65) | t(7)=8.79, p<0.001; 2.94 (1.29 to 4.57) | 4.86 (1.39) | t(6)=6.97, p<0.001; 2.47 (.93 to 3.98) |
| Pittsburg sleep quality index | 5.40 (.58) | 10.90 (1.03) | t(18)=4.66, p<0.001; 2.00 (.92 to 3.04) | 4.50 (1.10) | t(7)=5.53, p=0.001; 1.85 (.68 to 2.98) | 4.43 (.84) | t(6)=8.29, p<0.001; 2.93 (1.17 to 4.68) |
| Secondary CBT-I outcomes | |||||||
| Dysfunctional beliefs and attitudes about sleep | 3.26 (.33) | 6.18 (.42) | t(18)=5.52, p<0.001; 2.37 (1.21 to 3.48) | 3.24 (.33) | t(7)=7.18, p<0.001; 2.40 (.99 to 3.78) | 3.11 (.59) | t(6)=7.43, p<0.001; 2.63 (1.01 to 4.23) |
| Self-reported active disease (PRO-3) | 50% | 60% | X2 (1, N=20)=0.20, p=0.65 | 0% | McNeman’s Test p=0.03 | 12.5% | McNeman’s Test p=0.38 |
Bolded values are significant, though should be interpreted with caution given our small sample size.
*n=8 participants had complete diary data.
†The last week of CBT-I treatment data were used for each participant in data analyses.
‡n=8 participants had questionnaire data.
§n=7 participants had questionnaire data.
CBT-I, cognitive–behavioural therapy for insomnia; PRO-3, patient-reported outcome-3.