Coexisting sleep disturbances and depressive symptoms : treatment effects and mechanism of the integrative body-mind-spirit group intervention

Abstract

Background. Co-existing sleep disturbances and depressive mood are frequently observed in various clinical and community populations. During recent decades, increasing attention has been paid to sleep disturbances, especially insomnia, treating it as an independent disorder, especially when it co-occurs with other mental and physical illnesses. Moreover, sleep/wake dysregulations have been proposed as transdiagnostic processes across various emotional disorders as complex overlap/interactions in aetiology have been found to underlie sleep disturbances and mental disorders. Integrative Body-mind-spirit (I-BMS), proposed as one of the transdiagnostic approaches, were adopted to address the comorbid issue by incorporating mind-body exercise, spiritual activities into psychological group work. Emerging, but still rare, psychosocial interventions have been developed to address the comorbid issue, but there is even less investigation of the interplay between changes in sleep disturbances and mood symptoms in a group intervention context.Objective. This thesis has three aims: 1) to understand demographic and clinical features of the help-seeking population for mind-body interventions who self-reported insomnia and mood distress; 2) to evaluate the effectiveness of I-BMS on concomitant syndromes (sleep and mood disturbances) and participants’ holistic wellbeing based on theoretical hypotheses of I-BMS; 3) to investigate the interplay between changes in sleep quality and mood symptoms in the context of I-BMS intervention and to understand the treatment mechanisms embedded in symptom improvements. Methods. Three studies were conducted to fulfil the study objectives. The main design of the study is a randomized, waitlist controlled (WLC) trial based on a community online survey. Firstly, 699 participants were selected from the survey pool who reported elevated sleep disturbances with Pittsburgh Sleep Quality Index (PSQI) global scoring greater than five. A series of descriptive and regression analyses were performed to understand patterns of sleep disturbance symptoms in association with depressive mood among this help-seeking population. Secondly, an evaluation of the effectiveness of I-BMS group work (eight sessions on a weekly basis) was conducted. In total, this study recruited 185 eligible participants with self-reported insomnia and mild to moderate depression symptoms who were randomly assigned into two groups (I-BMS group, n = 92; WLC group, n = 93). Primary outcome measures include PSQI and Centre for Epidemiologic Studies Depression Scale (CESD); secondary outcomes include holistic measures on the bodily, mind and spiritual aspects. Lastly, linear regressions and path analyses were used to unravel the mechanisms underlying sleep and mood improvements found in Study 2. Results. In the current help-seeking population, 80 per cent of the participants reported insomnia/poor sleep quality for more than one year and 77.1 per cent of participants had clinically significant depressive symptoms. Older people were prone to report better mental health conditions compared to younger people.Subjective sleep quality, sleep disturbances and daytime dysfunction were independently associated with CESD groupings and severity of elevated depressive symptoms. There was also a significant interaction between sleep quality and CESD groupings in daytime impairment of participants: for those with significant depressive symptoms, poor sleep quality was more associated with daytime distress compared to those with subclinical syndromes. As for the effectiveness of I-BMS, intention to treat (ITT) analyses (multiple imputations and mixed linear modelling) showed that I-BMS can significantly improve sleep quality [F(2, 438) = 8.00, p < 0.001)] and mood symptoms [F(2, 441) = 7.93, p < 0.001)] with large effect size (SE: 0.74–1.94). Meanwhile, I-BMS also successfully targeted somatic afflictions, emotional dysregulations and hope levels posited as indicators for holistic wellness. The third study revealed a reciprocal association between sleep quality improvements and alleviation of depression immediately after treatment. However, at the follow-up visit, improvement in sleep quality seemed to account for mood improvement, but not vice versa. Path analyses further showed the mediating effect of PSQI improvements on CESD reduction with excellent model fit (χ2 = 8.31, p = 0.503, df = 17; RMSEA < 0.001; CFI = 1.000; TLI = 1.009), where daytime functioning served as a linking variable associating night-time sleep quality with mood symptoms. In addition, changes in depressive mood, but not sleep improvements, are associated with a wide range of process variables. Forward multiple mediation analyses revealed that immediately after attending the I-BMS classes, learning of non-attachment, among other process variables, significantly mediated relationships between treatment conditions and depressive symptom improvement that indicated nurturing of an acceptance attitude towards sleep and mood disruptions.Discussion. Comorbid conditions of physical illness and mental distress are commonly reported among current help-seeking populations. Complex relations between sleep parameters and depressive symptoms have been shown by analysing baseline data. I-BMS has been found to be a feasible and promising mind-body treatment for concurrent sleep and mood disturbances. There are reciprocal associations between sleep quality improvement and alleviation of depressive symptoms at post-treatment. Daytime functioning has been identified as a linking variable between them. Improvement of depressive symptoms was associated with a wide range of body-mind-spirit variables and improvement of sleep quality may be related to components specifically targeted through sleep attitude. Conclusion and implications. Complex interplays are involved in sleep and mood conditions. I-BMS is an effective intervention for the featured community populations which may target the common mechanisms underlying sleep and mood disturbances through body-mind-spirit integration, and sleep quality improvement can consistently predict mood enhancement. Integrative care models need to be developed and adapted to various populations who report both mind and bodily distress. Nevertheless, more efforts are required to understand links (protective and risk factors) between sleep problems and emotional disorders in both epidemiological and intervention studies in order to optimize treatments.