How does cognitive behavioural therapy for insomnia work? A systematic review and meta-analysis of mediators of change

Effect of cognitive behavioral therapy for insomnia on sleep quality among college students: the role of hyperarousal and dysfunctional beliefs

BACKGROUND

Although cognitive-behavioral therapy for insomnia (CBT-I) is an effective treatment for sleep disorders, little is known about the role of hyperarousal (especially trait arousal) in CBT-I interventions. Therefore, this study investigated the role of trait arousal in the maintenance of sleep problems using cross-sectional and longitudinal methods.

METHODS

Study 1, 1209 Chinese university students (63.9% female) completed the Dysfunctional Beliefs and Attitudes about Sleep (DBAS-16), Pre-sleep Arousal Scale (PSAS), Arousal Predisposition Scale (APS), and Pittsburgh Sleep Quality Index (PSQI). The study calculated the moderating role of trait arousal in the relationship between dysfunctional beliefs about sleep and sleep quality. In study two, 89 participants completed the questionnaire used in Study 1 during pre-and post-treatment. A within-subjects mediation analysis examined the indirect effects of dysfunctional beliefs about sleep pre-sleep arousal (cognitive and somatic) on sleep quality. A within-subjects moderation analysis was used to investigate whether baseline trait arousal moderated sleep quality.

RESULTS

Cross-sectional findings indicated that pre-sleep cognitive arousal mediated the effects of dysfunctional beliefs about sleep on sleep quality and that trait arousal moderated the first half of the mediating pathway described above; longitudinal analyses indicated that changes in dysfunctional beliefs about sleep and pre-sleep cognitive arousal mediated changes in sleep quality, and that, in addition, trait arousal moderated changes in sleep quality.

CONCLUSION

Trait arousal correlates with the maintenance of sleep problems, and participants with higher trait arousal benefited less from CBT-I. Enhancement programs that incorporate mindfulness may be a direction for future research.

Effectiveness of a guided digital self-help intervention to improve sleep and the biological clock in university students - Study protocol for a randomized controlled trial

Background

Sleep problems occur in many university students which affects their mental health and daily functioning. Cognitive behavioural therapy for insomnia (CBT-I) has been proven effective in adults but research in university students, who struggle to maintain a 24-hour rhythm, is still limited. We hypothesize that a guided digital CBT-I intervention, enriched with components on the biological clock ('i-Sleep & BioClock') will be effective in reducing insomnia severity and improving mental health outcomes for students with sleep problems.

Objectives

We aim to evaluate the effectiveness of a guided online sleep and biological clock self-help intervention in improving sleep, depression symptoms, anxiety symptoms, functioning, academic performance, and quality of life in university students at 6 weeks and 18 weeks.

Methods

This is a two-arm parallel-group superiority randomized controlled trial, comparing a 5-week guided online 'i-Sleep & BioClock' intervention to online psychoeducation (PE). We aim to include 192 university students (Bachelor, Master, and PhD) with at least subthreshold insomnia (Insomnia Severity Index ≥10), aged ≥16, who can speak Dutch or English. We are excluding students with current risk for suicide or night shifts. The primary outcome is insomnia severity. Secondary outcomes include sleep estimates (sleep and light exposure diary), depression, anxiety, functioning, quality of life, and academic performance. The effectiveness of the intervention compared to online PE will be evaluated using linear mixed models.

Discussion

The current study tests the effectiveness of an online self-help intervention for university students who suffer from sleep problems. This trial builds upon an open feasibility study and will provide evidence of an online guided self-help program for students. The findings of this study will determine the potential wider dissemination of the intervention to address the high need for available and accessible help for students experiencing insomnia.

Trial registration

ClinicalTrials.Gov (NCT06023693), registered on August 3rd, 2023.

Investigating the efficacy of digital cognitive behavioural therapy in comparison to a sleep-monitoring application via integrated diary and actigraphy: A randomised-controlled trial

Dissemination of digital cognitive behavioural therapy is a promising approach for treating insomnia in the broad population. Current evidence supports the effectiveness of the digital format, but clinical findings are often limited by the choice of control group and lack of in-depth therapeutic measures. This study was designed to investigate the specific effects of digital cognitive behavioural therapy in comparison to a self-monitoring application. Participants meeting criteria for insomnia were randomly allocated (1:1) to 8 weeks of digital cognitive behavioural therapy or 8 weeks of digital sleep monitoring (control application). The primary outcome, insomnia severity, was assessed at baseline, 8- and 16-weeks post-randomisation. Secondary outcomes included the assessment of sleep via application-integrated sleep diaries and actigraphy. Linear-mixed models were fitted to assess between-group differences. Fifty-six participants (48 females, mean age: M = 45.55 ± 13.70 years) were randomised to either digital cognitive behavioural therapy (n = 29) or digital sleep monitoring (n = 27). At 8- and 16-weeks post-randomisation, large treatment effects (d = 0.87-1.08) indicated robust reductions (-3.70 and -2.97, respectively; p ≤ 0.003) in insomnia severity in the digital cognitive behavioural therapy arm, relative to digital sleep monitoring. Treatment effects in favour of digital cognitive behavioural therapy were also found for self-reported and actigraphy-derived sleep continuity variables, indicating that sleep improved throughout the 8-week intervention period. Our study reinforces the role of digital cognitive behavioural therapy in achieving clinical improvements for patients with insomnia, affirming previous findings and supporting the specific effects of cognitive behavioural therapy.

A Pilot Randomized Trial of Combined Cognitive-Behavioral Therapy and Exercise Training Versus Exercise Training Alone for the Management of Chronic Insomnia in Obstructive Sleep Apnea

Insomnia treatment among individuals with comorbid insomnia and obstructive sleep apnea is suboptimal. In a pilot randomized controlled trial, 19 individuals with comorbid insomnia and obstructive sleep apnea were allocated to one of two arms: EX + EX, consisting of two 8-week phases of exercise training (EX), or RE + CBTiEX, encompassing 8 weeks of relaxation training (RE) followed by 8 weeks of combined cognitive-behavioral therapy and exercise (CBTiEX). Outcomes included Insomnia Severity Index (ISI), polysomnography, and cardiorespiratory fitness measures. A mixed-model analysis of variance revealed a Group × Time interaction on peak oxygen consumption change, F(1, 14) = 10.1, p = .007, and EX increased peak oxygen consumption (p = .03, g' = -0.41) and reduced ISI (p = .001, g' = 0.82) compared with RE (p = .49, g = 0.16) post-8 weeks. Post-16 weeks, there was a significant Group × Time interaction (p = .014) driven by RE + CBTiEX yielding a larger improvement in ISI (p = .023, g' = 1.48) than EX + EX (p = .88, g' < 0.1). Objective sleep was unchanged. This study showed promising effects of regular EX alone and combined with cognitive-behavioral therapy for insomnia on ISI in comorbid insomnia and obstructive sleep apnea.

Do changes in beliefs and behaviours moderate improvement in insomnia after acquired brain injury?

Key mechanisms of change in cognitive behavioural therapy for insomnia in the general population encompass changing sleep-related beliefs and behaviours. In a population with acquired brain injury, cognitive behavioural therapy for insomnia is effective as well, but little is known about the mechanisms of change. The aim of this study was to evaluate how changing sleep-related beliefs and behaviours were associated with improvement in insomnia following blended cognitive behavioural therapy for insomnia in a population with acquired brain injury. A secondary analysis was performed on data of a randomized-controlled trial, including 24 participants that received blended cognitive behavioural therapy for insomnia, and 24 participants that received treatment as usual. Results showed that following blended cognitive behavioural therapy for insomnia, significantly more participants improved on dysfunctional beliefs and sleep-related behaviours and this was associated to improvement in insomnia severity. For sleep-related behaviours, the association between improvement on behaviour and improvement on insomnia was significantly moderated by blended cognitive behavioural therapy for insomnia. However, the relation between dysfunctional beliefs and insomnia was not moderated by type of treatment. Similar results were found for acquired brain injury-adapted versions of the questionnaires in which up to half of the items were excluded as they could be regarded as not dysfunctional for people with acquired brain injury. These results show that improvement on insomnia severity is related to improvement in dysfunctional beliefs and behaviours, and cognitive behavioural therapy for insomnia efficacy may be moderated by the improvement in behaviours in particular. A focus on these behaviours can enhance treatment efficacy, but caution is needed regarding the behaviours that may reflect adequate coping with the consequences of the acquired brain injury.

Psychological inflexibility as a predictor associated with insomnia

Psychological flexibility has recently attracted the attention of researchers in the field of sleep disorders; therefore, in the study, psychological flexibility was evaluated as a predictor or factor related to the presence/severity of insomnia. We included 2218 individuals selected from the randomized-control trial for behavioural therapy for insomnia and cross-sectional studies, including 1797 individuals with insomnia and 421 controls without insomnia. All participants completed the DSM-5-based insomnia diagnosis interview, Insomnia Severity Index, Hospital Anxiety and Depression Scale, and Acceptance Action Questionnaire-II. Linear regression and multinomial logistic regression models were used. Sex, education, occupation, marital status, anxiety, depression and psychological inflexibility were possible predictors or factors associated with the severity of insomnia. Multivariate linear regression analysis demonstrated that sex (𝛽 = 0.88; t = 2.80; p = 0.005), depression (𝛽  = 0.41; t = 10.7; p < 0.001), anxiety (𝛽  = 0.58; t = 14.1; p < 0.001) and psychological inflexibility (𝛽  = 0.09; t = 5.07; p < 0.001) were predictors of insomnia. The results of the multinomial logistic regression demonstrate that, in comparison to the absence of insomnia, insomnia at all levels (mild, moderate and severe) was associated with sex, anxiety and depression. Psychological inflexibility was only associated with severe insomnia (odds ratio = 1.04). These findings are important from a public health perspective because behavioural strategies designed to treat insomnia with a focus on psychological flexibility are low-cost and may help improve sleep quality in adults with insomnia, which also influences mental health.

Cross-sectional analyses of factors associated with the presence and aggravation of chronic insomnia by symptom subtypes

Aim

The aim of this study was to investigate the association of psychological and chronobiological factors with the presence and severity of chronic insomnia by symptom subtypes and their impacts on daytime dysfunctions.

Methods

Participants of the present web-based epidemiological study were classified as follows: difficulty initiating sleep (DIS) (n = 91); difficulty maintaining sleep (DMS) (n = 13); early morning awakening (EMA) (n = 48); DIS + DMS (n = 67); DIS + EMA (n = 23); DMS + EMA (n = 24); triplet of DIS, DMS, and EMA symptoms (TRP) (n = 69); and normal sleepers (n = 4590). The Insomnia Severity Index (ISI), Hospital Anxiety and Depression Scale (HADS), Munich Chronotype Questionnaire (MCTQ), insomnia-related psychological measures (including the Ford Insomnia Response to Stress Test [FIRST] and the Dysfunctional Beliefs and Attitudes about Sleep Scale [DBAS]), and the cognitive and somatic domains of the Pre-Sleep Arousal Scale (PSAS) were evaluated.

Results

The presence of DIS and DIS + DMS were significantly associated with an evening preference, and EMA and EMA + DMS with a morning preference, while TRP showed no significant association with either chronotype. The increase in DBAS scores was associated with higher ISI scores in all subtypes. Meanwhile, the associations of each psychological measure varied among insomnia subtypes, with the association of PSAS cognitive arousal to DIS and PSAS somatic arousal to both DMS + EMA and TRP. Pathological HADS score was associated with all subtypes.

Conclusion

Chronotypes may be associated with the presence of some insomnia subtypes; however, only psychological factors were speculated to contribute to the aggravation of all subtypes. All insomnia subtypes possibly contribute to the formation of depression.

Changes in sleep effort mediate insomnia severity in older adults following online cognitive behavioural therapy

BACKGROUND

To examine treatment mechanisms of digitally delivered cognitive behavioural therapy for insomnia (CBT-I), this study assessed the mediating effects of dysfunctional beliefs, hyperarousal, locus of control, self-efficacy, sleep effort, and safety behaviours on self-reported insomnia severity in older adults before and following the completion of a self-guided, online CBT-I program.

METHODS

The baseline and follow-up measurements were completed by 62 older adults (55 female, 89%). This was a two-condition within-participant design. Mediation analysis using a parallel mediation model was conducted using the MEMORE macro for repeated measure designs.

RESULTS

Out of all the included mediator variables, only a reduction in sleep effort scores (0.88; SE 0.51; 95% CI 0.001-2.00) significantly mediated changes in insomnia severity scores following the intervention. Insomnia severity scores significantly reduced following the intervention (Mpre  = 9.84, SD = 5.89, Mpost  = 6.87, SD = 4.90); t(61) = 5.19, P = <0.001; d = 0.55 95% CI 0.38-0.93.

CONCLUSIONS

Sleep in older adults improved following digitally delivered CBT-I, and these changes were influenced by a reduction in sleep control efforts exerted by participants. These findings highlight possible treatment pathways of CBT-I. Further investigation of CBT-I as a strategy to prevent sleep problems is warranted.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry (ANZCTR), ACTRN 12619001509156; http://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=378451.

The sleep-circadian interface: A window into mental disorders

Sleep, circadian rhythms, and mental health are reciprocally interlinked. Disruption to the quality, continuity, and timing of sleep can precipitate or exacerbate psychiatric symptoms in susceptible individuals, while treatments that target sleep-circadian disturbances can alleviate psychopathology. Conversely, psychiatric symptoms can reciprocally exacerbate poor sleep and disrupt clock-controlled processes. Despite progress in elucidating underlying mechanisms, a cohesive approach that integrates the dynamic interactions between psychiatric disorder with both sleep and circadian processes is lacking. This review synthesizes recent evidence for sleep-circadian dysfunction as a transdiagnostic contributor to a range of psychiatric disorders, with an emphasis on biological mechanisms. We highlight observations from adolescent and young adults, who are at greatest risk of developing mental disorders, and for whom early detection and intervention promise the greatest benefit. In particular, we aim to a) integrate sleep and circadian factors implicated in the pathophysiology and treatment of mood, anxiety, and psychosis spectrum disorders, with a transdiagnostic perspective; b) highlight the need to reframe existing knowledge and adopt an integrated approach which recognizes the interaction between sleep and circadian factors; and c) identify important gaps and opportunities for further research.

Identifying the insomnia-related psychological issues associated with hyperarousal: A network perspective

Hyperarousal, recognized as a fundamental characteristic of insomnia for decades, has yielded limited evidence concerning its direct psychological associations. This study aimed to explore the psychological factors linked to hyperarousal within the framework of interrelated variables. Two independent samples, comprising n = 917 and n = 652 young adults, were included in the study. Employing the first dataset as a discovery sample and the second dataset as a replication sample, network analyses were conducted using 26 variables derived from 17 scales. The objective was to estimate the direct and indirect associations between psychological issues, including hyperarousal and insomnia. Additionally, linear regression analysis was employed to assess the convergence of findings obtained from the network analysis. Network analyses in both samples converged to reveal direct associations between insomnia severity and several psychological factors, including negative sleep beliefs, physical fatigue, insomnia response to stress, hyperarousal, self-reported depression, and mental fatigue. Notably, the nodes with relative importance within the network include trait anxiety, depressive rumination, hyperarousal, perfectionism sub-dimension of concern over mistakes, and private self-consciousness. Hyperarousal is one of the key factors linking insomnia with a variety of psychological issues, including emotion-related factors (rumination, perveived stress), sleep-related factors (dysfunctional sleep beliefs and attitudes, insomnia response to stress, fatigue, chronotype), and self-related factors (self-consciousness, perfectionism). The results suggest that forthcoming strategies for enhancing the treatment efficacy of insomnia could consider supplementary interventions that specifically address hyperarousal, other factors directly linked to insomnia, or the hub nodes within the network.

Cognitive factors and processes in models of insomnia: A systematic review

Cognition is central to the experience of insomnia. Although unhelpful thoughts about and around insomnia are a primary treatment target of cognitive behaviour therapy for insomnia, cognitive constructs are termed and conceptualised differently in different theories of insomnia proposed over the past decades. In search of consensus in thinking, the current systematic review identified cognitive factors and processes featured in theoretical models of insomnia and mapped any commonality between models. We systematically searched PsycINFO and PubMed for published theoretical articles on the development, maintenance and remission of insomnia, from inception of databases to February, 2023. A total of 2458 records were identified for title and abstract screening. Of these, 34 were selected for full-text assessment and 12 included for analysis and data synthesis following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We identified nine distinguishable models of insomnia published between 1982 and 2023 and extracted 20 cognitive factors and processes featured in these models; 39 if sub-factors were counted. After assigning similarity ratings, we observed a high degree of overlap between constructs despite apparent differences in terminologies and measurement methods. As a result, we highlight shifts in thinking around cognitions associated with insomnia and discuss future directions.

A comprehensive insight on cognitive behavioral therapy for insomnia in pregnant women: A systematic review and meta-analysis

BACKGROUND

Cognitive behavioral therapy for insomnia (CBT-I) as a first-line treatment may improve insomnia in pregnant women. The efficacy of the components, modalities, doses, and effectiveness of CBT-I in pregnant women at follow-up remains unclear.

OBJECTIVES

To assess the effectiveness of CBT-I in pregnant women and identify effective intervention components, modalities, and doses.

DESIGN

Systematic review and meta-analysis.

METHODS

Six English databases (PubMed, Embase, Cochrane Library, Web of Science, PsycINFO, CINAHL) and four Chinese databases (CNKI, WanFang Data, SinoMed, and CQVIP) were searched from inception to 10 January 2023. Randomized controlled trials (RCTs) on CBT-I in pregnant women with outcomes of insomnia severity measured by Insomnia Severity Index (ISI) or sleep quality measured by Pittsburgh Sleep Quality Index (PSQI). Two reviewers independently completed records selection, data extraction, and study quality assessment. The fixed-effect or random-effect model was used for pooled analyses. Subgroup analyses were conducted based on different delivery types and intervention duration. The GRADE approach was used to evaluate the certainty of the evidence. Narrative analyses were used when meta-analysis was not appropriate. Mean differences with 95% CIs of insomnia severity and sleep quality scores were the main outcomes (greater scores indicating greater severity).

RESULTS

Nine RCTs (N = 978) meeting the inclusion criteria were included. These trials included individual- (n = 6) or group-based (n = 3) interventions, which were conducted via face-to-face (n = 5), digital (n = 3) or telephone and e-mail (n = 1) formats. Six studies stated intervention components specific to pregnant women. CBT-I improved insomnia severity (MD = -2.69, 95% CI: -3.41 to -1.96, P ＜ 0.001, high quality evidence; MD = -3.69, 95% CI: -5.91 to -1.47, P = 0.001, moderate quality evidence) and sleep quality (MD = -2.85, 95% CI: -4.73 to -0.97, P = 0.003, moderate quality evidence; MD = -1.88, 95% CI: -2.89 to -0.88, P ＜ 0.001, moderate quality evidence) immediately after intervention (＜1-month) and at short-term (≥1 month to ＜6 months) follow-up, respectively. Two RCTs reported no effectiveness on insomnia severity at medium-term (≥6 months to＜12 months) follow-up. Only 1 RCT showed reduced insomnia severity at long-term (≥12 months) follow-up. One RCT reported no effectiveness in sleep quality at medium-term follow-up and effectiveness at long-term follow-up was not reported.

CONCLUSIONS

Pregnant women may benefit from CBT-I to improve short-term insomnia, but long-term effectiveness is unclear. Rigorous RCTs with long-term follow-ups are warranted.

Mechanisms of cognitive behavioural therapy for insomnia

Although much is known now about behavioural, cognitive and physiological consequences of insomnia, little is known about changes after cognitive behavioural therapy for insomnia on these particular factors. We here report baseline findings on each of these factors in insomnia, after which we address findings on their changes after cognitive behavioural therapy. Sleep restriction remains the strongest determinant of insomnia treatment success. Cognitive interventions addressing dysfunctional beliefs and attitudes about sleep, sleep-related selective attention, worry and rumination further drive effectiveness of cognitive behavioural therapy for insomnia. Future studies should focus on physiological changes after cognitive behavioural therapy for insomnia, such as changes in hyperarousal and brain activity, as literature on these changes is sparse. We introduce a detailed clinical research agenda on how to address this topic.

Challenging beliefs for quality sleep: A systematic review of maladaptive sleep beliefs and treatment outcomes following cognitive behavioral therapy for insomnia

Cognitive behavioral therapy for insomnia (CBT-I) is an empirically supported intervention for insomnia. Given the strong, consistent support of its efficacy, scholars have become increasingly interested in the behavioral and cognitive mechanisms targeted during CBT-I. The purpose of the systematic review was to synthesize findings from the literature regarding the associations among maladaptive sleep beliefs, a cognitive mechanism implicated in maintaining insomnia, and treatment outcomes following CBT-I. The systematic review was completed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Seventeen studies were included in the final sample of reviewed articles and a study quality assessment was performed for all studies included in the review. The results suggested that reductions in maladaptive sleep beliefs were associated with improved insomnia severity; however, reductions in maladaptive beliefs were not associated with changes in sleep efficiency or other sleep parameters. Moreover, in some cases, improved sleep parameters preceded reductions in maladaptive beliefs. Maladaptive sleep beliefs may be an important target for improving insomnia. Targeting maladaptive sleep beliefs may initiate a trickle-down process that limits the influence of other cognitive and behavioral processes maintaining insomnia. Additional investigation is needed to evaluate the directional relationship between improved insomnia symptoms and reduced maladaptive beliefs.

Dysfunctional beliefs and attitudes about sleep (DBAS) mediate outcomes in dCBT-I on psychological distress, fatigue, and insomnia severity

OBJECTIVE/BACKGROUND

Digital cognitive behavioral therapy for insomnia (dCBT-I) improves several sleep and health outcomes in individuals with insomnia. This study investigates whether changes in Dysfunctional Beliefs and Attitudes about Sleep (DBAS) during dCBT-I mediate changes in psychological distress, fatigue, and insomnia severity.

PATIENTS/METHODS

The study presents a secondary planned analysis of data from 1073 participants in a randomized control trial (Total sample = 1721) of dCBT-I compared with patient education (PE). Self-ratings with the Dysfunctional Beliefs and Attitudes about Sleep (DBAS), the Hospital Anxiety Depression Scale (HADS), the Chalder Fatigue Scale (CFQ), and the Insomnia Severity Index (ISI) were obtained at baseline and 9-week follow-up. Hayes PROCESS mediation analyses were conducted to test for mediation.

RESULTS AND CONCLUSION

sDBAS scores were significantly reduced at 9-week follow-up for those randomized to dCBT-I (n = 566) compared with PE (n = 507). The estimated mean difference was -1.49 (95% CI -1.66 to -1.31, p < .001, Cohen's d. = 0.93). DBAS mediated all the effect of dCBT-I on the HADS and the CFQ, and 64% of the change on the ISI (Estimated indirect effect -3.14, 95% CI -3.60 to -2.68) at 9-week follow-up compared with PE. Changes in the DBAS fully mediated the effects of dCBT-I on psychological distress and fatigue, and the DBAS partially mediated the effects on insomnia severity. These findings may have implications for understanding how dCBT-I works and highlights the role of changing cognitions in dCBT-I.

Association of Sleep Reactivity and Anxiety Sensitivity with Insomnia-Related Depression and Anxiety among City Government Employees in Japan

It has recently been noted that a reduction in sleep reactivity, characterized as the trait-like degree to which exposure to stress interferes with sleep, and anxiety sensitivity are associated with reduced insomnia severity. This study aimed to examine whether sleep reactivity and anxiety sensitivity are associated with insomnia-related depression and anxiety among city government employees in Japan. This cross-sectional study included 1810 city government employees of Koka City, Japan (mean age (standard deviation): 45.33 (12.20) years) who completely answered the scales for sleep reactivity, anxiety sensitivity, anxiety, and depression. Stepwise multiple regression analysis adjusted for demographic data showed that anxiety sensitivity (β = 0.39) was significantly linked to anxiety, and sleep reactivity (β = 0.36) was significantly linked to depression in individuals with insomnia. Additionally, the results of a logistic regression analysis adjusted for demographic data showed that anxiety sensitivity and sleep reactivity were relevant factors for anxious insomnia (OR = 12.69) and depressive insomnia (OR = 8.73), respectively. Whereas both sleep reactivity (OR = 14.67) and anxiety sensitivity (OR = 6.14) were associated with combined insomnia. These findings indicate that sleep reactivity is strongly associated with depressive symptoms, and anxiety sensitivity is strongly associated with anxiety symptoms in individuals with insomnia.

Mediators of outcome in adolescent psychotherapy and their implications for theories and mechanisms of change: a systematic review

Psychotherapeutic treatment of adolescents requires age-specific approaches and thus plausibly also involves different change mechanisms than adult psychotherapy. To guide further research and improve therapeutic outcomes for adolescents, we reviewed all RCTs investigating mechanisms of change in the psychological treatment of adolescents to identify the most promising age-, disorder- or treatment-specific mediators. Following the preferred reporting items for systematic reviews (PRISMA), 106 studies were included that reported 252 statistical mediation tests assessed with 181 different measures. Most often studied and significant mediators were cognitive, followed by family-related, and behavioral variables. Several mediators were identified to be promising for future investigations: changes in negative thoughts, dysfunctional beliefs and metacognitive skills; family functioning and parenting skills; as well as successful engagement in therapy activities and increased impulse control. Symptom change during therapy was least often a mediator for other therapeutic changes. Relational and emotional mediators were largely understudied, whereas peer-influence appeared a promising mediator for intervention outcomes. Adolescence-specific mediators were most commonly investigated. Majority of studied mediators were not disorder-specific. There was a tendency to mainly test change mechanisms of specific theoretical models without considering other possible change theories. Further, virtually no studies fulfilled all criteria for rigorously investigating mediation and only nine were classified with an overall good study quality. While bearing in mind the current limitations in study designs, methodological rigor and reporting, there appears to be substantial evidence for transdiagnostic age-specific change models in the psychological treatment of adolescents. For future research, need for consensus on a core set of transdiagnostic and transtheoretical mediators and measures is highlighted. These should address likely core mechanisms of change, as well as take into account age-relevant developmental challenges and biological markers.

Exercise as an Adjunct Treatment to Cognitive Behavior Therapy for Insomnia

The question that guided this review is whether exercise can add to the improvements in insomnia in patients treated with cognitive behavioral therapy for insomnia (CBT-I). CBT-I has long been recommended as the first-line treatment of chronic insomnia. However, CBT-I is not effective for as many as 30% to 40% of patients with insomnia. There is accumulating evidence for positive effects on insomnia following acute and chronic exercise. However, to the best of our knowledge, the effects of CBT-I combined with exercise have not been explored in clinical trials. In this article, we develop a rationale for combining CBT-I with exercise.

Subjective versus objective sleep outcomes in older adults with and without uncoupled sleep following online cognitive behavioural therapy for insomnia

BACKGROUND

Uncoupled sleep is a phenomenon characterised by a disconnect between sleep pattern and sleep complaint. This study examined the impact of uncoupled sleep on dysfunctional sleep beliefs and objective and subjective sleep outcomes in community-dwelling older adults following digitally delivered Cognitive Behavioural Therapy for Insomnia (CBT-I) to assess how these groups respond to CBT-I.

METHODS

Objective sleep was measured using wrist actigraphy, subjective sleep quality via sleep diaries and the Pittsburgh Sleep Quality Index (PSQI). Dysfunctional sleep beliefs were assessed by the Dysfunctional Beliefs and Attitudes about Sleep scale (DBAS-16). All measurements were taken prior to and following a 4-week online CBT-I program. Linear mixed model and generalised linear mixed model analyses were conducted to examine objective and subjective sleep onset latency, total sleep time, wake after sleep onset and number of awakenings as well as PSQI and DBAS-16 scores, respectively.

RESULTS

Out of 80 enrolled participants, 62 participants (55 females, 89%; 16 complaining good sleepers, 26 complaining poor sleepers, 11 non-complaining good sleepers, and nine non-complaining poor sleepers) completed the study. CBT-I reduced dysfunctional sleep beliefs across all sleeper classifications. Objective and self-reported changes in sleep parameters were demonstrated in complaining poor sleepers without uncoupled sleep. Complaining good sleepers with uncoupled sleep only reported a decrease in the number of subjective sleep awakenings. There were no changes in sleep outcomes in non-complaining good and non-complaining poor sleepers.

CONCLUSIONS

Online CBT-I was effective in improving the sleep outcomes of individuals who had both subjective and objective poor sleep. However, as the online CBT-I reduced dysfunctional sleep beliefs in all sleep groups, further examination of dysfunctional sleep beliefs and whether they mediate the outcomes of digital CBT-I in older adults will need to be conducted.

Hypnotic Medications as an Adjunct Treatment to Cognitive Behavioral Therapy for Insomnia

Cognitive behavioral therapy for insomnia (CBT-I) is the universally recommended treatment of choice for insomnia disorder based on its safety and posttreatment durability of benefit. However, CBT-I does not help all patients achieve remission. The second most evidence-based treatment, hypnotic pharmacotherapy (PCT), does not resolve perpetuating factors of insomnia, resulting in potential waning of benefit and dependence. This article presents a rationale that supports consideration of hypnotic augmentation of CBT-I (COMB), along with a review of select randomized controlled trials relevant to clinical decision-making.

The Role of Dysfunctional Sleep Beliefs in Mediating the Outcomes of Web-Based Cognitive Behavioral Therapy for Insomnia in Community-Dwelling Older Adults: Protocol for a Single-Group, Nonrandomized Trial

BACKGROUND

Sleeping well is an essential part of good health. Older adult populations report a high rate of sleep problems, with recent studies suggesting that cognitive processes as well as behavioral and hyperarousal-related mechanisms could be important factors in the development and maintenance of insomnia. Individuals who have an asynchronous or uncoupled sleep pattern and sleep appraisal-those who complain about their sleep but do not have poor sleep quality, and vice versa-might show differences in subjective sleep and sleep perceptions and other characteristics that could impact their treatment outcomes following cognitive behavioral therapy for insomnia (CBT-I).

OBJECTIVE

The purpose of this protocol is to describe the rationale and methods for a nonrandomized, single-arm trial assessing objective and subjective sleep quality in community-dwelling older adults aged 60-80 years with synchronous sleep patterns and sleep appraisal compared to those in older adults with asynchronous sleep patterns and sleep appraisal. The trial will further examine the role of cognitive, behavioral, and hyperarousal processes in mediating the treatment outcomes of web-based CBT-I.

METHODS

This trial aims to recruit a sample of 60 participants, who will be assigned to 1 of 4 sleep groups based on their sleep pattern and sleep appraisal status: complaining good sleepers, complaining poor sleepers, noncomplaining good sleepers, and noncomplaining poor sleepers, respectively. The trial will be completed in 2 phases: phase 1 will assess objective sleep (measured via wrist actigraphy) and subjective (self-reported) sleep. Phase 2 will investigate the impact of a web-based CBT-I program on the sleep outcomes of individuals with uncoupled sleep compared to that of individuals without uncoupled sleep, as well as the mediators of CBT-I.

RESULTS

Recruitment began in March 2020, and the last participants were recruited by March 2021. A total of 65 participants completed phases 1 and 2. Data analysis for phase 1 was finished in December 2021, and data analysis for phase 2 was finalized in July 2022. The results for phase 1 were submitted for publication in March 2022, and those for phase 2 will be submitted by the end of December 2022.

CONCLUSIONS

This trial will provide guidance on factors that contribute to the variability of sleep in older adults and their sleep outcomes following CBT-I. The outcomes of this study could be valuable for future research attempting to tailor CBT-I to individual needs.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12619001509156; https://tinyurl.com/69hhdu2w.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/32705.

Therapy for insomnia with chronic obstructive pulmonary disease: a randomized trial of components

STUDY OBJECTIVES

To determine efficacy and mechanisms of cognitive behavioral therapy for insomnia (CBT-I) and chronic obstructive pulmonary disease (COPD) education (COPD-ED) on clinical outcomes in adults with concurrent COPD and insomnia.

METHODS

We conducted a 2 × 2 factorial study to test the impact of CBT-I and COPD-ED delivered alone or in combination on severity of insomnia and fatigue, sleep, and dyspnea. Participants were randomized to 1 of 4 groups-group 1: CBT-I + attention control (AC; health videos, n = 27); group 2: COPD-ED + AC, n = 28; group 3: CBT-I + COPD-ED, n = 27; and group 4, AC only, n = 27. Participants received six 75-minute weekly sessions. Dependent variables included insomnia severity, sleep by actigraphy, fatigue, and dyspnea measured at baseline, immediately postintervention, and at 3 months postintervention. Presumed mediators of intervention effects included beliefs and attitudes about sleep, self-efficacy for sleep and COPD, and emotional function.

RESULTS

COPD patients (percent predicted forced expiratory volume in 1 second [FEV1pp] 67% ± 24% [mean ± standard deviation]), aged 65 ± 8 years, with insomnia participated in the study. Insomnia and sleep improved more in patients who received CBT-I than in those who did not, an effect that was sustained at 3 months postintervention and mediated by beliefs and attitudes about sleep. CBT-I was associated with clinically important improvements in fatigue and dyspnea. When CBT-I and COPD-ED were concurrently administered, effects on insomnia, fatigue, and dyspnea were attenuated.

CONCLUSIONS

CBT-I produced significant and sustained decreases in insomnia improved sleep and clinically important improvement in fatigue, and dyspnea. The combination of CBT-I and COPD-ED reduced CBT-I's effectiveness. Further research is needed to understand the mechanisms associated with effects of insomnia therapy on multiple symptoms in COPD.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: A Behavioral Therapy for Insomnia Co-existing with COPD; URL: https://clinicaltrials.gov/ct2/show/NCT01973647; Identifier: NCT01973647.

CITATION

Kapella M, Steffen A, Prasad B, et al. Therapy for insomnia with chronic obstructive pulmonary disease: a randomized trial of components. J Clin Sleep Med. 2022;18(12):2763-2774.

How Does E-mail-Delivered Cognitive Behavioral Therapy Work for Young Adults (18-28 Years) with Insomnia? Mediators of Changes in Insomnia, Depression, Anxiety, and Stress

This study examined whether cognitive behavioral therapy (CBT) for insomnia (CBT-I) improved insomnia severity, by changing sleep-related mediating factors. It also examined whether an improvement in insomnia led to enhanced mental health. This study was a secondary analysis of a randomized controlled trial of e-mail-delivered CBT-I for young adults with insomnia. The participants were randomized to either CBT-I or self-monitoring. The mental health-related measures were depression, anxiety, and stress. The sleep-related mediating factors were sleep hygiene practices, dysfunctional beliefs, sleep reactivity, and pre-sleep arousal. A total of 41 participants, who completed all the sessions (71% females; mean age 19.71 ± 1.98 years), were included in the analysis. The hierarchical multiple regression analysis showed that 53% of the variance in the improvements in insomnia severity was explained by the treatment group (β = −0.53; ΔR2 = 0.25; p < 0.01) and the changes in sleep reactivity (β = 0.39; ΔR2 = 0.28; p < 0.05). Moreover, the mediation analysis showed that the reductions in depression and stress were explained by the changes in insomnia severity; however, anxiety symptoms were not reduced. CBT-I for young adults suggested that sleep reactivity is a significant mediator that reduces insomnia severity, and that the alleviation and prevention of depression and stress would occur with the improvement in insomnia.

Using network intervention analysis to explore associations between participant expectations of and difficulties with cognitive behavioural therapy for insomnia and clinical outcome: A proof of principle study

BACKGROUND

Research about predictors of response to cognitive behaviour therapy for insomnia (CBT-I) is ongoing. We examined any whether pre-intervention expectations or post-intervention appraisals of difficulties in utilizing face to face (FtF) or digital (dCBT-I) versions of the therapy were associated with outcome.

METHODS

Self-rating data were extracted on 101 adult participants in a recent randomized controlled trial of FtF versus dCBT-I. Network intervention analyses were used to explore any associations between expectations of CBT-I at response at 9 weeks and between post-intervention ratings of difficulties, modality of therapy and response at 9-weeks and at 6-months.

RESULTS

Anticipated and actual difficulties in employing sleep restriction techniques predicted response in all network models. Modality of therapy played a more overt role in the 9-week outcome network, with FtF therapy more robustly associated with response. However, the direct association between FtF therapy and response was not found in the 6-month outcome network. Notable predictors of poor outcome at 9-weeks and 6-month follow-up were difficulties in accommodating CBT-I into work and daily routines and applying the rules of CBT-I.

CONCLUSIONS

This network intervention analysis highlights that self-confidence and ability in undertaking sleep restriction is a key active ingredient of CBT-I. Also, benefits and gains from access to the FtF version of this multi-component therapy were more apparent in the short than the longer term. However, it is important that findings from this proof of principle study are confirmed in further studies.

The effect of sleep restriction therapy for insomnia on sleep pressure and arousal: a randomised controlled mechanistic trial

STUDY OBJECTIVES

Sleep restriction therapy (SRT) effectively treats insomnia but mechanisms are poorly understood. Theoretical models suggest that potentiation of sleep pressure and reduction of arousal are key mechanisms of action. To our knowledge this has never been directly tested. We designed a randomised controlled trial with embedded mechanistic measurement to investigate if SRT causally modifies multidimensional assessments of sleep pressure and arousal.

METHODS

Participants aged 25-55 who met DSM-5 diagnostic criteria for insomnia disorder were randomised to four weeks of SRT or time in bed regularisation (TBR), a control intervention that involves prescription of a regular but not reduced time in bed. Sleep pressure was assessed through daily diary appraisal of morning and evening sleepiness, weekly Epworth sleepiness scale (ESS) scores, psychomotor vigilance, and NREM delta power (0.75-4.5Hz) from ambulatory polysomnographic recordings. Arousal was assessed through daily diary appraisal of cognitive arousal, the pre-sleep arousal scale (PSAS), and NREM beta power (15-32Hz). Outcomes were assessed at baseline (2-week period prior to randomisation), during the intervention phase (1-4 weeks post-randomisation), and at 12-week follow-up. We performed intention-to-treat analyses using linear mixed models. For continuous daily measures, the treatment period was split into early (weeks 1-2) and late (weeks 3-4) treatment.

RESULTS

Fifty-six participants (39 females, mean age=40.78±9.08) were assigned to SRT (n=27) or TBR (n=29). The SRT group showed enhanced sleep pressure relative to TBR, reflected in (1) enhanced sleepiness in the evening during early (d=1.17) and late treatment (d=0.92), and in the morning during early treatment (d=0.47); (2) higher daytime sleepiness on the ESS at weeks-1 and -2 (d=0.54, d=0.45); and (3) reduced psychomotor vigilance at week-1 (d=0.34). The SRT group also showed reduced arousal relative to TBR, reflected in lower levels of daily-monitored cognitive arousal during early treatment (d=0.53) and decreased PSAS total score at week-4 and week-12 (ds≥0.39). Power spectral analysis of all night NREM sleep revealed an increase in relative, but not absolute, EEG delta power at week-1 and week-4 (ds≥0.52) and a decrease of relative EEG beta power at week-4 (d=0.11).

CONCLUSION

For the first time we show that SRT increases sleep pressure and decreases arousal during acute implementation, providing support for mechanism-of-action.

An Empirical Research of the Mechanism from Electric Vehicle Production to Charging Station R&D in China

Electric vehicles (EVs) are regarded as an effective method for dealing with serious environmental pollution. The Chinese government has implemented a series of incentives to accelerate the promotion of EV. However, the increasing production of EVs gives rise to a greater demand for better quality charging station. This study aimed to certify the impact of the production of EVs on charging station research and development (R&D) in China, with mediating effect methods and a panel fixed effect model. The conclusions derived from the study were: (1) Statistically, the production of EVs positively and significantly impacts charging station R&D; (2) the mediating role of investment in charging stations is verified in the relationship between the production of EVs and charging station R&D; (3) environmental tax can moderate the relationship between the production of EVs and charging station R&D. These results implicate, for the first time, that the production of EVs can enhance charging station R&D through the mediating role of charging station investments and the moderating role of environmental tax.