The sample consisted of 22 women and 8 men, who ranged in age from 19 to 65 years old and were well-educated. () The majority (80%) were working full or part-time. History of insomnia complaints ranged from 1 to 30 years, with a median duration of 6 years. At screening, two-thirds of the patients were using sleep medications, either prescription or over-the-counter, and 20% had previously tried eszopiclone. Medical co-morbidities were common, with almost half the sample (46%) reporting two or more. Baseline characteristics were reasonably balanced across study arms, however the number of patients who reported a history of depression or an anxiety disorder was somewhat higher in the MBSR arm.
Participant Characteristics at Randomization
Sleep diaries completed for 14-days prior to randomization confirmed poor sleep: mean SOL = 44.5 minutes; mean WASO= 55.5 minutes; mean TST = 6.3 hours; and mean SE = 75.3%. Actigraphy-derived averages for this period were similar to the diary values for TST (mean 6.4 hours), WASO (mean 58.5 minutes) and SE (77%), and somewhat shorter than the diary values for SOL (means 34.6 vs. 44.5 minutes, Mann-Whitney U test, P=.05). Self-report scales also confirmed sleep problems at baseline. The average score on the ISI was consistent with moderate insomnia (mean =17.1, SD = 3.34, ISI range of 12 to 24), and all patients scored above 7, the cutoff for no insomnia. All participants were in the PSQI “poor sleep” range at baseline and the average PSQI score was 11.6 (SD=2.53, range from 8 to 18). No significant differences were found at baseline on actigraphy-derived sleep parameters or on the standardized sleep scales between treatment groups, however, based on diary reports, WASO was perceived to be somewhat shorter (46.6 vs. 72.6 minutes, P =0.11) and SE somewhat higher (77.3% vs. 71.7%, P = 0.07) in the group randomized to MBSR than in the PCT arm.
No statistically significant differences were found between MBSR and PCT groups over time on sleep or quality of life outcomes, based on repeated measures ANOVAs. Lack of difference does not confirm equivalence, however, as the sample size was not sufficient to establish the non-inferiority of MBSR to PCT for sleep treatment. Consistent with the pilot objectives, changes within each group are described below.
Sleep Diary Outcomes
Sleep diaries were completed every morning for 2 weeks at 3 time points: pre-treatment baseline, the end of the active intervention period, and the end of follow-up. Sleep diary results are shown in . In the MBSR arm, diary-based SOL, WASO, and SE significantly improved from baseline to the end of the active intervention period, providing medium-sized treatment effects (ds = -.57, -.46, and .61, respectively; Ps<.01, all). A treatment impact of MBSR on TST emerged by 5-month follow-up. Whereas the impact on WASO appeared to wane, it is notable that other treatment effects in the MBSR arm increased with longer follow-up; medium to large treatment effects for TST, SOL and SE (ds = .69, .79, and -.80, respectively; Ps<.01, all) by 5-months. In the PCT arm, diary-based TST, WASO, and SE significantly improved from baseline to the end of the active intervention period, and these improvements were sustained, with large treatment effects from baseline to 5 months (ds = .92, -.97, and 1.29, respectively). While not statistically significant, there is a suggestion that MBSR may impact SOL more than PCT (mean change at follow-up: -22.2 vs. -4.65 minutes for MBSR vs. PCT).
Sleep Diary Parameters by Treatment Group and Time
Actigraphs were worn at two points, in time in tandem with completion of the sleep diaries at pre-randomization, and the end of the active intervention period. Actigraphy results are shown in . A statistically significant 8.9 minute decrease in actigraphy-derived SOL was found within the MBSR arm (d = -.31, P = .04), consistent with the perceptions of shorter times to fall asleep that these patients recorded in their diaries. Other actigraphy changes in the MBSR arm were small (ds < |.22|) and not statistically significant. In the PCT arm, however, actigraphy-derived TST and SE parameters significantly improved (ds = .63 and .52, respectively; Ps<.05, both), and while not statistically significant, the average WASO decreased 14.8 minutes.
Actigraphy Sleep Parameters by Treatment Group and Time
Standardized Sleep Scales and Quality of Life Measures
Standardized sleep scales are shown in . The MBSR group reported large, statistically significant improvements from baseline to follow-up on all self-reported sleep measures at 8-weeks and at 5-months (|ds| ranging from .8 to 2.4, Ps<0.01, all). Large treatment impacts were also noted in the PCT arm, although due to the smaller sample size, some results were not statistically significant. and depict the individual trajectories of change for the ISI and PSQI by treatment group; reduced symptoms are visible by 8-weeks, and many patients reported continued improvement through the end of follow-up.
Sleep Scales and Health-related Quality of Life by Treatment Group and Time
FIGURE 2 Scores on the Insomnia Severity Index are shown by patient and treatment arm, at baseline, 8-weeks and 5-months. Each line represents one patient. Patients in the MBSR arm are represented by solid dots, and patients in the PCT (eszopiclone) arm are represented (more ...)
FIGURE 3 Scores on the Pittsburgh Sleep Quality Index are shown by patient and treatment arm, at baseline, 8-weeks and 5-months. Each line represents one patient. Patients in the MBSR arm are represented by solid dots, and patients in the PCT (eszopiclone) arm (more ...)
Health-related quality of life results are shown at the bottom of . Insomnia-related activity impairment was significantly reduced in the MBSR group at both 8-weeks and 5-months (P
= -1.1 and -.80). The impact on activity impairment in the PCT arm was similar, but not significant due to the smaller sample size. By 5-month follow-up, symptoms of anxiety and depression decreased and mental health scores increased in both groups, but these changes were not statistically significant. The improvement in mental health approached significance in both arms (Ps
= .06 and .08) with mean changes of 4.6 to 5.8 points, exceeding accepted criteria for clinically important change.47
Recovery from Chronic Insomnia
All study participants met criteria for insomnia and poor sleep at baseline. Numbers of patients who experienced a reliable improvement and no longer met these criteria are shown in . By 5-months, over half the MBSR patients had recovered, based on the ISI and PSQI. Moreover, no patient experienced a clinically important deterioration in his or her insomnia, defined as an increase of 7 points on the ISI. Notably, about half the patients in the MBSR arm whose recorded sleep efficiency was below 85% at baseline had a reliable improvement by 5-month follow-up (7 of 13), and all but one of the MBSR patients whose total sleep time averaged less than 6 hours at baseline was reliably sleeping more than 6 hours per night at follow-up (4 of 5). Although not statistically significant, it is interesting to note that the rates of recovery from poor sleep, as measured by the PSQI, were considerably higher following MBSR than PCT at 8-weeks and at 5-months.
Clinical Significance of Self-Reported Outcomes
Adherence and Treatment Satisfaction
The study was completed with 2 MBSR programs (n's = 9 and 11). Eighteen out of 20 patients (90%) attended at least 5 MBSR classes, meeting the benchmark for course completion. Ten MBSR patients attended all 8 classes, and 16 of 20 attended the all-day retreat. In their follow-up questionnaires, 14 of the 18 MBSR patients in the outcome analyses (78%) reported no use of sleep medications (prescription or over-the-counter); 2 reported using sleep medications less than once a week and 2 reported use once or twice a week.
Nine out of 10 patients randomized to PCT took their assigned medication. Based on analysis of the electronic pill monitors (MEMS Caps®), over the first 8 weeks, three patients were 100% compliant with nightly dosing; two had over 90% compliance; and four took eszopiclone 4 to 6 nights each week. By the final study month, two patients discontinued eszopiclone completely and these patients reported using no other sleep medications. Six PCT patients continued use of eszopiclone through the last month of follow-up: two maintained nightly dosing; three took a dose 4 to 6 nights a week; and one used eszopiclone an average of 2 nights a week. One patient did not submit medication use data at 5-months.
Meditation home practice time was calculated based on electronic loggers submitted by 17 patients who completed MBSR. The average home practice time was 23.7 (SD = 11.2) minutes per day during the 8 week active intervention period. This represents 61% of the home practice expectation during this period (e.g., 45 minutes per day, 6 days a week), however time spent meditating during MBSR classes would boost these averages. Sixteen MBSR patients reported practice throughout follow-up, with an average of 21.8 minutes of practice per day during months 3 thru 5, consistent with follow-up practice expectations of 20 minutes per day. The median number of days practiced in the final week of the study was 4 days. Reductions in Dysfunctional Beliefs about Sleep scores and Activity Limitation due to Insomnia from baseline to month 5 were significantly predicted by home practice during the active intervention period (Spearman's rho correlations = 0.62 and 0.71, respectively, Ps<.02). Correlations with changes in other measures were smaller and not significant.
Treatment satisfaction and treatment preferences were evaluated at 5-month follow-up. Treatment satisfaction was rated on a 0 to 10 point scale from very dissatisfied to very satisfied. The satisfaction scores in the MBSR group were high, with a mean of 8.8. The average satisfaction score in the PCT group was lower, with a mean of 6.1. Treatment preference was ascertained by recall, using the question, “When you joined this study which treatment did you hope to be assigned to?” In the MBSR arm, 14 indicated MBSR, 2 PCT, and 2 no preference. In the PCT arm, 5 indicated MBSR, 2 PCT, and 1 no preference. There were no unexpected, serious adverse events related to the interventions in this trial. One PCT patient was switched from eszopiclone to controlled-release zolpidem during the first month of treatment because of persistent complaints of an extremely unpleasant after-taste. Other side effects reported in the PCT arm included excessive sleepiness, headache and dizziness. No adverse events related to MBSR were reported.