A randomized control trial for integrative body-mind treatment of insomnia and depression symptoms: Mechanism of improvement

Abstract

BACKGROUND Insomnia and depression are commonly coexist and interplay with each other. However, their interactions in an intervention outcome was rarely reported. The present study aimed to unravel this relationship and to identify predictors for insomnia and depression symptom reduction. Integrative body-mind-spirit (I-BMS) model has gained abundant supporting evidences on its effectiveness. METHODS Participants were recruited in online survey in 2013.Those who had mild to moderate depression and insomnia symptoms (10≤CES-D≤35 and PSQI>5) without psychotic comorbidity were invited to attend two-arm RCT (1=wait-list control,2=IBMS).Other measures include Holistic Well-being Scale (HWS) with Affliction and Equanimity subscales. Data collected at baseline (T0) and three-month follow-up (T2) was used (n of 1=56; n of 2=70).Symptoms improvement and affliction decrease was calculated by reduction rate at T2 (T0-T2/ T0).Increase of equanimity was the increase rate at T2 (T2- T0/ T0). Linear regression was firstly conducted to identify predictors for insomnia and depression reduction rate respectively. Then, mediation analysis was used to further explore relations between insomnia and depression improvement. RESULTS After considering baseline scores, groups and demographic factors, linear regression revealed that reduction rate of PSQI (B=0.42, p < 0.05) and that of spiritual disorientation (B=0.36, p < 0.01), a factor of affliction subscale, are strongly predictive of depression reduction. Shorter duration of insomnia (B=- 0.10, p < 0.001), higher baseline PSQI score (B=0.03,p < 0.001) and greater reduction rate of depression(B=0.11,p=0.04) can predict greater sleep improvement. Yet, no factors from HWS was found accounting for PSQI reduction rate. After considering co-variables, the effect of intervention on CES-D reduction rate was fully mediated by reduction rate of PSQI; bootstrapped indirect effect was 0.11. Meanwhile, reduction rate of CES-D slightly mediated the effect of I-BMS on reduction rate of PSQI; indirect effect was 02. Likewise, two-way paths also exited between remission of daytime dysfunction and CES-D reduction with relatively equivalent indirect effect (0.10-0.12), which was not found on nighttime insomnia symptoms. CONCLUSION This study indicated a bi-directional pathway existing between improvement of insomnia symptom, especially daytime functioning and depression remission. Thus, insomnia management is required in treatment of depression and vice versa. In addition, type and severity of patients’ symptom can predict treatment outcome which require more careful pre-assessment. In the context of I-BMS model, spiritual disorientation are strong indicators for depression reduction when it is comorbid with insomnia. In addition to behavior therapy, spiritual components should also be included in a comprehensive treatment.