Mediation analysis in psychosomatic medicine research

Study of a PST-trained voice-enabled artificial intelligence counselor for adults with emotional distress (SPEAC-2): Design and methods

BACKGROUND

Novel and scalable psychotherapies are urgently needed to address the depression and anxiety epidemic. Leveraging artificial intelligence (AI), a voice-based virtual coach named Lumen was developed to deliver problem solving treatment (PST). The first pilot trial showed promising changes in cognitive control measured by functional neuroimaging and improvements in depression and anxiety symptoms.

METHODS

To further validate Lumen in a 3-arm randomized clinical trial, 200 participants with mild-to-moderate depression and/or anxiety will be randomly assigned in a 2:1:1 ratio to receive Lumen-coached PST, human-coached PST as active treatment comparison, or a waitlist control condition where participants can receive Lumen after the trial period. Participants will be assessed at baseline and 18 weeks. The primary aim is to confirm neural target engagement by testing whether compared with waitlist controls, Lumen participants will show significantly greater improvements from baseline to 18 weeks in the a priori neural target for cognitive control, right dorsal lateral prefrontal cortex engaged by the go/nogo task (primary superiority hypothesis). A secondary hypothesis will test whether compared with human-coached PST participants, Lumen participants will show equivalent improvements (i.e., noninferiority) in the same neural target from baseline to 18 weeks. The second aim is to examine (1) treatment effects on depression and anxiety symptoms, psychosocial functioning, and quality of life outcomes, and (2) relationships of neural target engagement to these patient-reported outcomes.

CONCLUSIONS

This study offers potential to improve the reach and impact of psychotherapy, mitigating access, cost, and stigma barriers for people with depression and/or anxiety.

CLINICALTRIALS

gov #: NCT05603923.

Combining mindfulness and cognitive training in children with attention deficit hyperactivity disorder: study protocol of a pilot randomized controlled trial (the NeuroMind study)

Introduction

Attention Deficit Hyperactivity Disorder (ADHD) has a global mean prevalence of 5%. Cognitive Training (CT) and Mindfulness-Based Interventions (MBIs) have shown promising results in managing ADHD symptoms, but they are not its Treatment-As-Usual (TAU). The NeuroMind Study aims to evaluate the preliminary effectiveness and feasibility of three interventions: Mindfulness for Health (M4H), CT using the NeuronUP® platform (CT), and a combination of both, Mindfulness Cognitive Training (MCT). There is empirical evidence supporting the effectiveness of the M4H and NeuronUP® platform; however, this study explores for the first time the effectiveness of MCT and CT, as well as the integration of M4H into TAU. The objectives of this 5-month Randomized Controlled Trial (RCT) are: (1) To analyze the preliminary effectiveness and feasibility of M4H, CT or a combination of both (MCT) added to TAU for children with ADHD; (2) To evaluate the role of psychological process variables (mindfulness and emotional regulation) as mediators of 5-month follow-up clinical outcomes; (3) To preliminarily explore whether specific sociodemographic and clinical characteristics can predict the short-and medium-term clinical response to the specific treatments.

Methods and analysis

Participants will be 120 children (7 to 12 years) with ADHD recruited at Child and Adolescent Mental Health Service (CAMHS) Sant Joan de Déu Terres de Lleida (Spain) randomly allocated to one of the four study arms: TAU vs. TAU + CT vs. TAU + M4H vs. TAU + MCT. An assessment to collect ADHD symptoms, Executive Functions (EF), comorbid symptoms and global functioning will be conducted pre-intervention, post-intervention (2 months after baseline) and at the 5-month follow-up. Linear mixed models and mediational models will be computed.

Discussion

If the preliminary effectiveness and feasibility of the MCT are demonstrated, this study could be a preliminary basis to do a full RCT with a larger sample to definitively validate the intervention. The MCT could be applied in clinical practice if it is definitively validated.Clinical trial registration:ClinicalTrials.gov, identifier, NCT05937347. https://clinicaltrials.gov/study/NCT05937347?locStr=Spain&country=Spain&cond=ADHD&intr=Mindfulness&rank=1.

The Comorbidity of Patient-Reported Crohn's Disease Activity and Depression: The Role of Health Behavior Mediators

Background

Longitudinal research reveals a unidirectional relationship between a nonsomatic symptom of depression, a negative view of the self, and later reported Crohn's disease (CD) activity. We evaluated whether health behaviors mediated this association using a longitudinal design.

Methods

We studied 3304 adult volunteers with a self-reported diagnosis of CD who completed a baseline survey that included demographics, CD activity, a symptom-specific index of depression, and measures of physical activity, smoking, and sleep quality. Crohn's disease status and the cognitive index of depression were also measured 6 and 12 months after the baseline evaluation. We specified single-mediator and multiple-mediator models to elucidate the depression-disease activity relationship.

Results

Among 2395 females and 909 males, we found a significant mediation effect for activity level (P < .001) after adjusting for age, sex, and body mass index. There was no evidence that sleep quality and smoking are significant single mediators. When we considered multiple mediation models, smoking and less activity partially mediate the depression-CD association.

Conclusions

Smoking and lower levels of physical activity are potential mediators of the unidirectional association between a nonsomatic symptom of depression-a negative view of the self-and patient-reported CD activity. Evaluating and treating specific symptoms of depression may reduce the frequency of CD exacerbations.

A sensitivity analysis for temporal bias in cross-sectional mediation

For over three decades, methodologists have cautioned against the use of cross-sectional mediation analyses because they yield biased parameter estimates. Yet, cross-sectional mediation models persist in practice and sometimes represent the only analytic option. We propose a sensitivity analysis procedure to encourage a more principled use of cross-sectional mediation analysis, drawing inspiration from Gollob and Reichardt (1987, 1991). The procedure is based on the two-wave longitudinal mediation model and uses phantom variables for the baseline data. After a researcher provides ranges of possible values for cross-lagged, autoregressive, and baseline Y and M correlations among the phantom and observed variables, they can use the sensitivity analysis to identify longitudinal conditions in which conclusions from a cross-sectional model would differ most from a longitudinal model. To support the procedure, we first show that differences in sign and effect size of the b-path occur most often when the cross-sectional effect size of the b-path is small and the cross-lagged and the autoregressive correlations are equal or similar in magnitude. We then apply the procedure to cross-sectional analyses from real studies and compare the sensitivity analysis results to actual results from a longitudinal mediation analysis. While no statistical procedure can replace longitudinal data, these examples demonstrate that the sensitivity analysis can recover the effect that was actually observed in the longitudinal data if provided with the correct input information. Implications of the routine application of sensitivity analysis to temporal bias are discussed. R code for the procedure is provided in the online supplementary materials. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The mediting role of psychological resilience on the negative effect of pain in patients with rheumatoid arthritis: A cross-sectional study

The objective of this study was to investigate the direct effects of pain-induced depression and anxiety, as well as the mediating role of psychological resilience, on the psychological distress associated with rheumatoid arthritis. The method involved a sample of 196 patients with rheumatoid arthritis and applied the Hospital Anxiety and Depression Scale, Connor-Davidson Resilience Scale, and visual analog scale for pain. Bivariate and path analyses were performed, and a multiple mediational model was utilized. Results showed that all correlations among study variables were significant (p < 0.01). A partial mediation effect of psychological resilience was observed, and direct effects among the variables (pain, psychological resilience, anxiety, and depression) were statistically significant, including the direct effect of psychological resilience on depression and anxiety. The indirect effects of pain through psychological resilience on depression and anxiety were also significant. Thus, the results suggest that psychological resilience partially mediates the effects of pain-induced anxiety and depression in patients with rheumatoid arthritis.

Pathways to mental well-being for graduates of mindfulness-based cognitive therapy (MBCT) and mindfulness-based stress reduction (MBSR): A mediation analysis of an RCT

OBJECTIVE

To explore mediated effects of Mindfulness-Based Cognitive Therapy-"Taking it Further" (MBCT-TiF) on mental well-being through changes in mindfulness, self-compassion, and decentering.

METHOD

A secondary analysis of an RCT using simple mediation, with 164 graduates of MBCT and mindfulness-based stress reduction (MBSR), was implemented whereby MBCT-TiF (vs ongoing mindfulness practice; OMP) was the independent variable; changes in mindfulness, self-compassion, and decentering during the intervention were the mediators; and mental well-being at post-intervention, whilst controlling for baseline, was the dependent variable. Secondary outcomes included psychological quality of life, depression, and anxiety.

RESULTS

Compared to OMP, MBCT-TiF experienced significant improvements in mental well-being through changes in all three mediators (mindfulness: ab = 0.11 [0.03, 0.25]; decentering: ab = 0.16 [0.05, 0.33]; self-compassion: ab = 0.07 [0.01, 0.18]). A similar pattern was demonstrated for depression, but only mindfulness and decentering mediated effects on psychological quality of life and anxiety.

CONCLUSION

The findings provide preliminary support for all three mediators in driving change in mental well-being in a sample of MBCT/MBSR graduates. Future work must be theory-driven and powered to test all mediators in parallel and alongside other potential mediators (e.g., equanimity) to further understand independent contributions and interacting effects.Trial registration: ClinicalTrials.gov identifier: NCT05154266.

Effectiveness of attachment-based compassion therapy to reduce psychological distress in university students: a randomised controlled trial protocol

Introduction

Higher education, particularly university, is a challenge for many students that can lead to their mental health being seriously affected. The stress to which they are subject throughout their time at university can lead to anxiety and depression. "Third wave" psychotherapies, including compassion-based therapy, have been used to improve psychological outcomes, such as stress, anxiety, emotional distress and well-being. There are some signs that third wave psychotherapies reduce psychological distress in university students, but more and higher-quality studies are needed. In this randomised controlled trial (RCT), we hypothesise that the provision of attachment-based compassion therapy (ABCT) will be more effective than an active control group based on relaxation therapy for improving psychological distress in university students.

Methods and analysis

A two-arm RCT will be conducted involving 140 university undergraduate and postgraduate students from the University of Zaragoza and the National University of Distance Education (UNED) who reside in the autonomous community of Aragon, Spain. Interventions with either ABCT or relaxation therapy will be implemented, with an allocation ratio of 1:1 between groups. Both interventions will last six weeks and consist of six weekly group sessions lasting 1.5 h each. Data will be collected before and after the intervention, and there will be a follow-up at six months. The primary outcome will be psychological distress at post-intervention. Secondary outcomes will be depression, anxiety, stress and burnout symptoms, affectivity and emotional regulation. Attachment style, experiential avoidance, compassion (for others/oneself) and mindfulness skills will be measured as potential mechanistic variables. Intention-to-treat analysis will be performed using linear mixed regression models. The clinical significance of improvements will be calculated. Potential side effects will be monitored by an independent clinical psychologist.

Ethics and dissemination

This study was approved by the Clinical Research Ethics Committee of Aragón. Participant data will remain anonymous, and results will be submitted to peer-reviewed open-access journals and disseminated via conferences.

Clinical Trial Registration

ClinicalTrials.gov, identifier NCT05197595.

Mindfulness skills and experiential avoidance as therapeutic mechanisms for treatment-resistant depression through mindfulness-based cognitive therapy and lifestyle modification

Background/objective

The COVID-19 pandemic and consequent physical distancing has made it difficult to provide care for those with Treatment-Resistant Depression (TRD). As a secondary analysis of a clinical trial, the aim of this study was to explore potential mechanisms through which three online-delivered approaches, added to treatment as usual, improve depressive symptoms in TRD patients.

Methods

The three approaches included (a) Minimal Lifestyle Intervention (MLI), (b) Mindfulness-Based Cognitive Therapy (MBCT), and (c) Lifestyle Modification Program (LMP). Sixty-six participants with TRD completed assessments pre-post intervention (mindfulness skills [FFMQ]; self-compassion [SCS]; and experiential avoidance [AAQ-II]) and pre-intervention to follow-up (depressive symptoms [BDI-II]). Data were analyzed using within-subjects regression models to test mediation.

Results

Mindfulness skills mediated the effect of MBCT on depressive symptoms (ab = −4.69, 95% CI = −12.93 to−0.32), whereas the lack of experiential avoidance mediated the effect of LMP on depressive symptoms (ab = −3.22, 95% CI = −7.03 to−0.14).

Conclusion

Strengthening mindfulness skills and decreasing experiential avoidance may promote recovery in patients with TRD, MBCT, and LMP have demonstrated that they may help increase mindfulness skills and decrease experiential avoidance, respectively. Future work will need to unpick the components of these interventions to help isolate active ingredients and increase optimization.

Mediation Analysis in Manual Therapy Research

Objective

The purpose of this study was to illustrate the applicability of mediation analysis in the manual therapy field by assessing whether pain intensity, duration of pain, or the change in systolic blood pressure mediated the heart rate variability (HRV) of patients with musculoskeletal pain who received manual therapy.

Methods

A secondary data analysis from a 3-arm, parallel, randomized, placebo-controlled, assessor-blinded, superiority trial was performed. Participants were randomized into spinal manipulation, myofascial manipulation, or placebo groups. Cardiovascular autonomic control was inferred from resting HRV variables (low-high frequency power ratio; LF/HF) and blood pressure responsiveness to a sympathoexcitatory stimulus (cold pressor test). Pain intensity and duration were assessed. Mediation models analyzed whether pain intensity, duration, or blood pressure independently affected the improvement of the cardiovascular autonomic control of patients with musculoskeletal pain after intervention.

Results

The first assumption of mediation was met for LF/HF with statistical evidence of a total effect of spinal manipulation, as compared with placebo on HRV outcomes (β = 0.77 [0.17-1.30]); second and third assumptions showed no statistical evidence of a relationship between the intervention and pain intensity (β = -5.30 [-39.48 to 28.87]), pain intensity, and LF/HF (β = 0.00 [-0.01 to 0.01]).

Conclusion

In this study of causal mediation analysis, the baseline pain intensity, duration of pain, and responsiveness of the systolic blood pressure to a sympathoexcitatory stimulus did not mediate the effects of the spinal manipulation on the cardiovascular autonomic control of patients with musculoskeletal pain. Accordingly, the immediate effect of spinal manipulation on the cardiac vagal modulation of patients with musculoskeletal pain may more likely be related to the intervention rather than the mediators investigated.

Social identities and the achievement gap: Incompatibility between social class background and student identity increases student disidentification, which decreases performance and leads to higher dropout rates

Education is not equally distributed across all people. It has often been found that students from low social class background have lower access to universities, less academic achievement and higher dropout rates compared with their peers (called the 'achievement gap'). We investigate how the student social identity contributes to the emergence of the achievement gap and focus on student disidentification, a negative internalized relation to the in-group. We predict that disidentification reduces academic performance (Hypothesis 1) and increases university dropout rates (Hypothesis 2). Moreover, we predict that social class background affects identity incompatibility which, in turn, increases student disidentification (Hypothesis 3). We explore whether social class background affects long-term identity incompatibility, or whether identity incompatibility affects long-term disidentification by comparing two mediation models. Hypotheses 1 and 3 were supported cross-sectionally in a large sample (N = 2768), and longitudinally in a sub-sample 1.5 years later (N = 591). The data demonstrate that social class background has a long-term effect on incompatibility, which is related to disidentification. Hypothesis 2 was also supported in a (partly overlapping) sub-sample (N = 1077). The current research demonstrates that students with low social class background suffer from identity-related adaptation problems that affect their academic trajectories.

Effectiveness, cost-utility and physiological underpinnings of the FIBROWALK multicomponent therapy in online and outdoor format in individuals with fibromyalgia: Study protocol of a randomized, controlled trial (On&Out study)

Introduction: The On&amp;Out study is aimed at assessing the effectiveness, cost-utility and physiological underpinnings of the FIBROWALK multicomponent intervention conducted in two different settings: online (FIBRO-On) or outdoors (FIBRO-Out). Both interventions have proved to be efficacious in the short-term but there is no study assessing their comparative effectiveness nor their long-term effects. For the first time, this study will also evaluate the cost-utility (6-month time-horizon) and the effects on immune-inflammatory biomarkers and Brain-Derived Neurotrophic Factor (BDNF) levels of both interventions. The objectives of this 6-month, randomized, controlled trial (RCT) are 1) to examine the effectiveness and cost-utility of adding FIBRO-On or FIBRO-Out to Treatment-As-Usual (TAU) for individuals with fibromyalgia (FM); 2) to identify pre–post differences in blood biomarker levels in the three study arms and 3) to analyze the role of process variables as mediators of 6-month follow-up clinical outcomes.

Methods and analysis: Participants will be 225 individuals with FM recruited at Vall d’Hebron University Hospital (Barcelona, Spain), randomly allocated to one of the three study arms: TAU vs. TAU + FIBRO-On vs. TAU + FIBRO-Out. A comprehensive assessment to collect functional impairment, pain, fatigue, depressive and anxiety symptoms, perceived stress, central sensitization, physical function, sleep quality, perceived cognitive dysfunction, kinesiophobia, pain catastrophizing, psychological inflexibility in pain and pain knowledge will be conducted pre-intervention, at 6 weeks, post-intervention (12 weeks), and at 6-month follow-up. Changes in immune-inflammatory biomarkers [i.e., IL-6, CXCL8, IL-17A, IL-4, IL-10, and high-sensitivity C-reactive protein (hs-CRP)] and Brain-Derived Neurotrophic Factor will be evaluated in 40 participants in each treatment arm (total n = 120) at pre- and post-treatment. Quality of life and direct and indirect costs will be evaluated at baseline and at 6-month follow-up. Linear mixed-effects regression models using restricted maximum likelihood, mediational models and a full economic evaluation applying bootstrapping techniques, acceptability curves and sensitivity analyses will be computed.

Ethics and dissemination: This study has been approved by the Ethics Committee of the Vall d’Hebron Institute of Research. The results will be actively disseminated through peer-reviewed journals, conference presentations, social media and various community engagement activities. Trial registration number NCT05377567 (clinicaltrials.gov).

Linear high-dimensional mediation models adjusting for confounders using propensity score method

High-dimensional mediation analysis has been developed to study whether epigenetic phenotype in a high-dimensional data form would mediate the causal pathway of exposure to disease. However, most existing models are designed based on the assumption that there are no confounders between the exposure, the mediators, and the outcome. In practice, this assumption may not be feasible since high-dimensional mediation analysis (HIMA) tends to be observational where a randomized controlled trial (RCT) cannot be conducted for some economic or ethical reasons. Thus, to deal with the confounders in HIMA cases, we proposed three propensity score-related approaches named PSR (propensity score regression), PSW (propensity score weighting), and PSU (propensity score union) to adjust for the confounder bias in HIMA, and compared them with the traditional covariate regression method. The procedures mainly include four parts: calculating the propensity score, sure independence screening, MCP (minimax concave penalty) variable selection, and joint-significance testing. Simulation results show that the PSU model is the most recommended. Applying our models to the TCGA lung cancer dataset, we find that smoking may lead to lung disease through the mediation effect of some specific DNA-methylation sites, including site Cg24480765 in gene RP11-347H15.2 and site Cg22051776 in gene KLF3.

Teacher-student relationships and adolescents' school satisfaction: Behavioural engagement as a mechanism of change

BACKGROUND

Teacher-student relationships have been linked to various aspects of students' school functioning, including social-emotional well-being in school, but the underlying mechanisms need more investigation.

AIMS

In this study, we analysed longitudinal data to test if students' classroom behavioural engagement was a potential mechanism of change that explained how teacher-student relationships affect student school satisfaction.

SAMPLE

We used an archival dataset with a sample of seventh graders (ages 11-14, M_age  = 12.7 year) in a middle school in the Southeastern United States.

METHODS

Adolescents completed self-report surveys across three waves over the course of 18 months.

RESULTS

Longitudinal structural equation modelling analyses revealed that teacher-student relationships were positively associated with positive classroom engagement behaviours and school satisfaction, respectively, at each time, and positive classroom behaviours at Time 2 fully mediated the longitudinal association between teacher-student relationships (Time 1) and school satisfaction (Time 3).

CONCLUSIONS

Taken together, results suggested that fostering positive teacher-student relationships to increase students' positive classroom behaviours could be an effective pathway to promote students' satisfaction with school. The applications of the results in educators' and psychologists' work, such as consultation and trainings with teachers, are discussed.

A preliminary model of football-related neural stress that integrates metabolomics with transcriptomics and virtual reality

Research suggests contact sports affect neurological health. This study used permutation-based mediation statistics to integrate measures of metabolomics, neuroinflammatory miRNAs, and virtual reality (VR)-based motor control to investigate multi-scale relationships across a season of collegiate American football. Fourteen significant mediations (six pre-season, eight across-season) were observed where metabolites always mediated the statistical relationship between miRNAs and VR-based motor control (pSobelperm≤ 0.05; total effect > 50%), suggesting a hypothesis that metabolites sit in the statistical pathway between transcriptome and behavior. Three results further supported a model of chronic neuroinflammation, consistent with mitochondrial dysfunction: (1) Mediating metabolites were consistently medium-to-long chain fatty acids, (2) tricarboxylic acid cycle metabolites decreased across-season, and (3) accumulated head acceleration events statistically moderated pre-season metabolite levels to directionally model post-season metabolite levels. These preliminary findings implicate potential mitochondrial dysfunction and highlight probable peripheral blood biomarkers underlying repetitive head impacts in otherwise healthy collegiate football athletes.

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Permutation-based mediation statistics can be applied to multi-scale biology problems

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Fatty acids were a critical link between elevated miRNAs and motor control

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HAEs interacted with pre-season metabolite levels to model post-season levels

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Together, our observations point to brain-related mitochondrial dysfunction

Relationships between care burden, resilience, and depressive symptoms among the main family caregivers of stroke patients: A cross-sectional study

OBJECTIVES

This study aims to explore the potential mediating role of resilience between care burden and depressive symptoms in family caregivers of stroke patients.

METHODS

A cross-sectional study was conducted with a convenience sample involving 245 main family caregivers of stroke patients recruited from the neurology department of a Tertiary A hospital in China. Mediation analyses were conducted using the PROCESS macro (Model 4) for SPSS, applying the Bootstrap analysis with 5,000 samples and a 95% confidence interval.

RESULTS

The results showed that with constant hemiplegia side, Barthel Index, education level, monthly income, care time per day, and living with patients in regression equations, the resilience partially mediated the correlation of care burden and depressive symptoms with a mediation effect ratio of 26.32%.

CONCLUSIONS

Resilience plays a mediating role in the correlation between care burden and depressive symptoms.

IMPACT

The findings indicated a protective effect of resilience in alleviating the negative influences of care burden on depressive symptoms, suggesting that resilience-training intervention may be developed to mitigate depressive symptoms of the main family caregivers of stroke patients.

Does Exposure to High Job Demands, Low Decision Authority, or Workplace Violence Mediate the Association between Employment in the Health and Social Care Industry and Register-Based Sickness Absence? A Longitudinal Study of a Swedish Cohort

BACKGROUND

The aim of this paper was to investigate if job demands, decision authority, and workplace violence mediate the association between employment in the health and social care industry and register-based sickness absence.

METHODS

Participants from the Swedish Longitudinal Occupational Survey of Health who responded to questionnaires in 2006-2016 (n = 3951) were included. Multilevel autoregressive cross-lagged mediation models were fitted to the data. Employment in the health and social care industry at one time point was used as the predictor variable and register-based sickness absence >14 days as the outcome variable. Self-reported levels of job demands, decision authority, and exposure to workplace violence from the first time point were used as mediating variables.

RESULTS

The direct path between employment in the health and social care industry and sickness absence >14 days was, while adjusting for the reverse path, 0.032, p = 0.002. The indirect effect mediated by low decision authority was 0.002, p = 0.006 and the one mediated by exposure to workplace violence was 0.008, p = 0.002. High job demands were not found to mediate the association.

CONCLUSION

Workplace violence and low decision authority may, to a small extent, mediate the association between employment in the health and social care industry and sickness absence.

Effectiveness of mindfulness-based stress reduction and attachment-based compassion therapy for the treatment of depressive, anxious, and adjustment disorders in mental health settings: A randomized controlled trial

OBJECTIVES

To study the effectiveness of attachment-based compassion therapy (ABCT) for reducing affective distress in a sample of outpatients with depressive, anxiety, or adjustment disorders, and to explore its mechanisms of action.

METHODS

This randomized controlled trial involved the assessment time points of pretreatment, posttreatment and 6-month follow-up. A total of 90 patients from three mental health units in Castellón, Spain, were recruited and randomly assigned to "ABCT + treatment as usual (TAU)," "Mindfulness-based stress reduction (MBSR) + TAU" or "TAU" alone. Affective distress, as measured by the "Depression, Anxiety and Stress Scales" (DASS-21) was the main outcome; self-compassion and mindfulness were also assessed. Multilevel mixed-effects models were used to estimate the effectiveness of the program, and path analyses were conducted to study the potential mechanistic role of mindfulness and self-compassion.

RESULTS

ABCT was not superior to MBSR in any outcome or at any assessment point. ABCT was superior to TAU alone both posttreatment (B = -13.20; 95% confidence interval [CI]: -19.57, -6.84) and at 6-month follow-up (B = -7.20; 95% CI: -13.63, -0.76) for reducing DASS-21, and MBSR was superior to TAU alone both posttreatment (B = -11.51; 95% CI: -17.97, -5.05) and at 6-month follow-up (B = -8.59; 95% CI: -15.09, -2.10), with large effects (d ≥ 0.90). Changes produced by ABCT in DASS-21 were mediated by self-compassion, whereas changes produced by MBSR were mediated by both mindfulness and self-compassion.

CONCLUSION

ABCT is effective for reducing affective distress in patients with anxiety, depressive and adjustment disorders, although its effect is not superior to that offered by MBSR. Self-compassion seems to be a significant mediator of the effects of ABCT.

Changes in Stress, Coping Styles, and Life Satisfaction between the First and Second Waves of the COVID-19 Pandemic: A Longitudinal Cross-Lagged Study in a Sample of University Students

In this study, we aimed to explain the interplay mechanism between stress, life satisfaction, and coping styles among university students. A cohort study was performed during the first (wave 1; W1) and second (wave 2; W2) waves of the Coronavirus disease 2019 (COVID-19) pandemic. The total sample included 231 university students, of which 59.31% were women. The Satisfaction with Life Scale (SWLS), Perceived Stress Scale (PSS), and Coping Inventory for Stressful Situations (CISS) were included in one online survey. Stress, emotion-oriented, and avoidance-oriented coping styles increased from W1 to W2 of the COVID-19 pandemic, while life satisfaction and task-oriented coping decreased. The partial mediation effect of all three coping styles during W1 and W2 (in a cross-sectional approach) on the relationship between perceived stress and life satisfaction was confirmed in this study. The task-oriented and avoidance-oriented coping styles can play a mediating role in the reciprocal relationship between life satisfaction and perceived stress during W1 and W2 of the pandemic. There were no mutual interactions between stress and life satisfaction from a longitudinal approach. Coping styles changed subsequently due to stressful environmental changes related to lockdown during the COVID-19 pandemic. Having a wide range of coping strategies from which to choose during an unstable situation should help manage stress and well-being.

The Mental Health and Wellbeing of University Students: Acceptability, Effectiveness, and Mechanisms of a Mindfulness-Based Course

Mental health problems are relatively common during university and adversely affect academic outcomes. Evidence suggests that mindfulness can support the mental health and wellbeing of university students. We explored the acceptability and effectiveness of an 8-week instructor-led mindfulness-based course ("Mindfulness: Finding Peace in a Frantic World"; Williams and Penman, 2011) on improving wellbeing and mental health (self-reported distress), orientation and motivation towards academic goals, and the mechanisms driving these changes. Eighty-six undergraduate and post-graduate students (>18 years) participated. Students engaged well with the course, with 36 (48.0%) completing the whole programme, 52 (69.3%) attending 7 out of 8 sessions, and 71 (94.7%) completing at least half. Significant improvements in wellbeing and mental health were found post-intervention and at 6-week follow-up. Improvements in wellbeing were mediated by mindfulness, self-compassion, and resilience. Improvements in mental health were mediated by improvements in mindfulness and resilience but not self-compassion. Significant improvements in students' orientation to their academic goal, measured by "commitment" to, "likelihood" of achieving, and feeling more equipped with the "skills and resources" needed, were found at post-intervention and at 6-week follow-up. Whilst exploratory, the results suggest that this mindfulness intervention is acceptable and effective for university students and can support academic study.

Impact of mindfulness and self-compassion on anxiety and depression: The mediating role of resilience

Background/Objective 'Third-wave' psychotherapies have shown effectiveness for treating psychopathological symptoms such as anxiety and depression. There is burgeoning interest in examining how these therapies' core constructs produce their therapeutic benefits. This study explores the hypothetical mediating effect of resilience in the impact of mindfulness and self-compassion on anxiety and depressive symptoms. Method: Cross-sectional study design. The sample consisted of 860 Spanish general population participants. The measures included the Mindful Attention Awareness Scale (MAAS), the Self-Compassion Scale (SCS-12), the Connor-Davidson Resilience Scale (CD-RISC) and the Goldberg Anxiety and Depression Scale (GADS). Bivariate correlations were calculated, and path analysis models were performed. Results: Significant correlations were found between the study variables, always in the expected direction (all p values <.001). The path analysis models showed significant direct effects of mindfulness and self-compassion on anxiety and depression symptoms, but the only significant indirect effects through resilience were found on depression (MAAS: β = -.05, 95% CI = -.11 to -.02; SCS-12: β = -.06, 95% CI = -.33 to -.07). Conclusions: Resilience might partially mediate the effect of mindfulness and self-compassion on depression, but not on anxiety.

Efficacy of a mindfulness-based programme with and without virtual reality support to reduce stress in university students: A randomized controlled trial

OBJECTIVES

To evaluate the efficacy of a mindfulness-based programme (MBP) for reducing stress in university students and its action mechanisms and to explore the capacity of virtual reality (VR) exposure to enhance adherence to the intervention.

METHODS

This randomized controlled trial (RCT) involved assessment time points of baseline, posttreatment, and 6-month follow-up. A total of 280 students from two Spanish universities were randomly assigned to 'MBP', 'MBP + VR', or 'Relaxation' (active controls). Perceived stress posttreatment was the primary outcome; wellbeing and academic functional outcomes were assessed as well. Multilevel mixed-effects models were performed to estimate the efficacy of the programme.

RESULTS

Both 'MBP' (B = -2.77, d = -0.72, p = .006) and 'MBP + VR' (B = -2.44, d = -0.59, p = .014) were superior to 'Relaxation' in improving stress, as well as most of the secondary outcomes, with medium-to-large effects posttreatment and at follow-up. The long-term effects of MBPs on stress were mediated by mindfulness and self-compassion in parallel. Treatment adherence was improved in the 'MBP + VR' group, with higher retention rates and session attendance (p < .001).

CONCLUSIONS

This RCT supports the efficacy of an MBP compared to relaxation for reducing stress in university students through mindfulness and self-compassion as mechanisms of change. VR exposure may enhance treatment adherence.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03771300.

Mediation effect selection in high-dimensional and compositional microbiome data

The microbiome plays an important role in human health by mediating the path from environmental exposures to health outcomes. The relative abundances of the high-dimensional microbiome data have an unit-sum restriction, rendering standard statistical methods in the Euclidean space invalid. To address this problem, we use the isometric log-ratio transformations of the relative abundances as the mediator variables. To select significant mediators, we consider a closed testing-based selection procedure with desirable confidence. Simulations are provided to verify the effectiveness of our method. As an illustrative example, we apply the proposed method to study the mediation effects of murine gut microbiome between subtherapeutic antibiotic treatment and body weight gain, and identify Coprobacillus and Adlercreutzia as two significant mediators.

Reducing stress and promoting well-being in healthcare workers using mindfulness-based cognitive therapy for life

Healthcare workers play a critical role in the health of a nation, yet rates of healthcare worker stress are disproportionately high. We evaluated whether mindfulness-based cognitive therapy for life (MBCT-L), could reduce stress in healthcare workers and target a range of secondary outcomes. Method: This is the first parallel randomised controlled trial of MBCT-L. Participants were NHS workers, who were randomly assigned (1:1) to receive either MBCT-L or wait-list. The primary outcome was self-reported stress at post-intervention. Secondary variables were well-being, depression, anxiety, and work-related outcomes. Mixed regressions were used. Mindfulness and self/other-compassion were explored as potential mechanisms of effects on stress and wellbeing. Results: We assigned 234 participants to MBCT-L (n = 115) or to wait-list (n = 119). 168 (72%) participants completed the primary outcome and of those who started the MBCT-L 73.40% (n = 69) attended the majority of the sessions. MBCT-L ameliorated stress compared with controls (B = 2.60, 95% CI = 1.63‒3.56; d = -0.72; p < .0001). Effects were also found for well-being, depression and anxiety, but not for work-related outcomes. Mindfulness and self-compassion mediated effects on stress and wellbeing. Conclusions: MBCT-L could be an effective and acceptable part of a wider healthcare workers well-being and mental health strategy.

Cannabis Use, Screen Time, and Internalizing Symptoms among Canadian Youth: Testing Mediation Pathways

Background: Existing research suggests positive correlations between screen time sedentary behaviors (STSB) and substance use, including cannabis use, among youth. However, little research has examined what factors mediate these relationships.Methods: This study examined mediating pathways among STSB, internalizing symptoms (IS), and cannabis use in a linked longitudinal sample of 28 269 Canadian youth who participated in the COMPASS study over a two-year period (2017/18 to 2018/19). Structural equation modeling examined two main hypotheses cross-sectionally and over time: 1) if IS mediated associations between STSB and cannabis use frequency, and 2) if STSB mediated associations between IS and cannabis use frequency. Results: Results demonstrated significant partial mediation effects for both hypotheses. For example, indirect effects indicated that IS mediated the association between STSB and cannabis use both cross sectionally (95% CI: 0.021, 0.029) and longitudinally (95% CI: 0.006, 0.010). STSB also mediated associations between IS and cannabis use cross sectionally (95% CI: 0.015, 0.023) and longitudinally (95% CI: 0.010, 0.014). This study demonstrated that the associations between STSB, internalizing symptoms and cannabis use are complex, involving mediation in both directions.Discussion: These findings can be used to inform public health initiatives that aim to take a comprehensive approach to addressing negative health behaviors and outcomes, as it is clear that the multi-directional relationships between STSB and mental health may in-turn impact other health behaviors. Future research should continue to examine mediating factors between STSB and substance use among youth, including exploration of associations with other substances.Supplemental data for this article is available online at https://doi.org/10.1080/10826084.2021.1922455 .

Qigong for the treatment of depressive symptoms: Preliminary evidence of neurobiological mechanisms

OBJECTIVES

Qigong has been shown to effectively reduce depressive symptoms in older adults with chronic physical illness. Here, we sought to evaluate the effects of qigong on serotonin, cortisol, and Brain-derived Neurotropic Factors (BDNF) levels and test their roles as potential mediators of the effects of qigong on depressive symptoms.

METHODS

Thirty older adults with chronic physical illness participated in a randomized clinical trial. They were randomly assigned to a qigong group (n = 14) or a control group for cognitive training of executive function and memory (n = 16). The participants provided blood and saliva samples at baseline and post-intervention. Levels of cortisol were measured from the salvia samples, and serotonin and BDNF were measured from the blood samples.

RESULTS

Consistent with the study findings presented in the primary outcome paper, a significant Group × Time interaction effect emerged on depressive symptoms, explained by greater reductions in the qigong group than the control group. Qigong participants had significantly larger increases in serotonin and BDNF, and decreases in cortisol levels, compared with control group participants. Moreover, treatment-related changes in cortisol levels (but not serotonin or BDNF) fully mediated the beneficial effects of qigong on depressive symptoms.

CONCLUSION

The findings provide preliminary evidence that treatment-related changes in cortisol may mediate the benefits of qigong on depressive symptoms. Given the limitation of small sample size of the present study, future studies with larger sample sizes and more extended follow-up assessment are warranted to determine the reliability of these findings.

A randomized controlled efficacy trial of mindfulness-based stress reduction compared with an active control group and usual care for fibromyalgia: the EUDAIMON study

Fibromyalgia (FM) syndrome represents a great challenge for clinicians and researchers because the efficacy of currently available treatments is limited. This study examined the efficacy of mindfulness-based stress reduction (MBSR) for reducing functional impairment as well as the role of mindfulness-related constructs as mediators of treatment outcomes for people with FM. Two hundred twenty-five participants with FM were randomized into 3 study arms: MBSR plus treatment-as-usual (TAU), FibroQoL (multicomponent intervention for FM) plus TAU, and TAU alone. The primary endpoint was functional impact (measured with the Fibromyalgia Impact Questionnaire Revised), and secondary outcomes included "fibromyalginess," anxiety and depression, pain catastrophising, perceived stress, and cognitive dysfunction. The differences in outcomes between groups at post-treatment assessment (primary endpoint) and 12-month follow-up were analyzed using linear mixed-effects models and mediational models through path analyses. Mindfulness-based stress reduction was superior to TAU both at post-treatment (large effect sizes) and at follow-up (medium to large effect sizes), and MBSR was also superior to FibroQoL post-treatment (medium to large effect sizes), but in the long term, it was only modestly better (significant differences only in pain catastrophising and fibromyalginess). Immediately post-treatment, the number needed to treat for 20% improvement in MBSR vs TAU and FibroQoL was 4.0 (95% confidence interval [CI] = 2.1-6.5) and 5.0 (95% CI = 2.7-37.3). An unreliable number needed to treat value of 9 (not computable 95% CI) was found for FibroQoL vs TAU. Changes produced by MBSR in functional impact were mediated by psychological inflexibility and the mindfulness facet acting with awareness. These findings are discussed in relation to previous studies of psychological treatments for FM.

Feasibility and Effectiveness of a Workplace-Adapted Mindfulness-Based Programme to Reduce Stress in Workers at a Private Sector Logistics Company: An Exploratory Mixed Methods Study

There is a high prevalence of stress in the logistics sector owing to very demanding, fast-paced and unpredictable tasks. Mindfulness-based programmes may reduce stress but require considerable practice. Our aim was to evaluate the feasibility and effectiveness of a shortened, workplace-adapted mindfulness-based programme for the logistics sector (WA-MBP-LS) for the purpose of reducing stress. A nonblinded, nonrandomised, two-arm controlled trial was conducted. The WA-MBP-LS (n = 32) consisted of six weekly 90-min mindfulness sessions. The control group (n = 36) attended a psycho-educational seminar. The Perceived Stress Scale (PSS) and Five Facets of Mindfulness Questionnaire (FFMQ) were measured at pretest, posttest and 6-month follow-up. Differences between groups were evaluated using mixed-effects models. Qualitative methods were used to analyse implementation issues. A 64.2% reduction was observed between initial volunteers and actual participants. Attrition at six-month follow-up was 45.6%. Participants attended a median of five sessions. Decreases in PSS favoured the WA-MBP-LS group at posttest and follow-up. FFMQ played a mediating role in PSS reductions. Barriers were disinterest, lack of programming, work overload and absences from work. Facilitators were curiosity, timing, company facilities and audio recordings. The WA-MBP-LS was feasible and effective in reducing stress, but more efforts to improve the practicalities of implementation are desirable.

The mediating role of depression in pathways linking positive and negative symptoms in schizophrenia. A longitudinal analysis using latent variable structural equation modelling

BACKGROUND

The interaction between positive, negative and depressive symptoms experienced by people with schizophrenia is complex. We used longitudinal data to test the hypothesis that depressive symptoms mediate the links between positive and negative symptoms.

METHODS

We analyzed data from the European Schizophrenia Cohort, randomly sampled from outpatient services in France, Germany and the UK (N = 1208). Initial measures were repeated after 6 and 12 months. Depressive symptoms were identified using the Calgary Depression Scale for Schizophrenia (CDSS), while positive and negative symptoms were assessed with the Positive and Negative Syndrome Scale (PANSS). Latent variable structural equation modelling was used to investigate the mediating role of depression assessed at 6 months in relation to the longitudinal association between positive symptoms at baseline and negative symptoms at 12 months.

RESULTS

We found longitudinal associations between positive symptoms at baseline and negative symptoms at 12 months, as well as between both of these and CDSS levels at 6 months. However depression did not mediate the longitudinal association between PANSS scores; all the effect was direct.

CONCLUSIONS

Our findings are incompatible with a mediating function for depression on the pathway from positive to negative symptoms, at least on this timescale. The role of depression in schizophrenic disorders remains a challenge for categorical and hierarchical diagnostic systems alike. Future research should analyze specific domains of both depressive and negative symptoms (e.g. motivational and hedonic impairments). The clinical management of negative symptoms using antidepressant treatments may need to be reconsidered.

Effects of attachment-based compassion therapy (ABCT) on brain-derived neurotrophic factor and low-grade inflammation among fibromyalgia patients: A randomized controlled trial

Fibromyalgia (FM) is a disabling syndrome characterized by chronic pain associated with fatigue. Its pathogenesis is unknown, but alterations in central sensitization, involving an imbalance of brain-derived neurotrophic factor (BDNF) and inflammatory biomarkers, appear to be implicated. The aim of this study was to evaluate the impact of attachment-based compassion therapy (ABCT) on levels of BDNF, the inflammatory markers TNF-α, IL-6, IL-10, and the C-reactive protein (CRP), analysing whether biomarkers play a mediating/moderating role in improvements in FM functional status. Thirty-four female patients with FM participated in a RCT and were assigned to ABCT or relaxation therapy. Blood extractions were conducted at baseline and post-intervention, with self-report assessments of functional status (FIQ) at baseline, post-intervention and 3-month follow-up. A pro-inflammatory composite was obtained by summing up IL-6, TNF-α and CRP normalized values. Non-parametric tests, analysis of variance and regression models were used to evaluate treatment and mediation/moderation. Compared to relaxation therapy, ABCT showed significant improvements in FIQ and decreases in BDNF, CRP, and pro-inflammatory composite. Changes in BDNF had a mediating role in FIQ. ABCT seems to reduce BDNF and appears to have anti-inflammatory effects in FM patients. Reductions in BDNF could be a mechanism of FM functional status improvement.

Clinical Trial Registration:http://ClinicalTrials.gov, identifier NCT02454244. Date: May 27th, 2015.

Attachment-based compassion therapy and adapted mindfulness-based stress reduction for the treatment of depressive, anxious and adjustment disorders in mental health settings: a randomised controlled clinical trial protocol

INTRODUCTION

Depressive, anxiety and adjustment disorders are highly prevalent among mental health outpatients. The lack of funding for mental health problems produces inefficient results and a high burden of disease. New cost-effective group interventions aimed at treating these symptoms might be an appropriate solution to reduce the healthcare burden in mental health units. Mindfulness-based interventions (MBIs) have shown significant reductions in anxious, depressive and adjustment symptomatology. Recent research highlights the influence of compassion as a key mechanism of change. However, MBIs only address compassion implicitly, whereas compassion-based protocols consider it a core aspect of psychotherapy. In this randomised controlled trial, we hypothesise that the provision of attachment-based compassion therapy (ABCT), which is a compassion-based protocol, will be more effective than mindfulness-based stress reduction (MBSR), which is a conventional MBI programme, for the treatment of depressive, anxious and adaptive symptoms in patients in mental health settings.

METHODS AND ANALYSIS

Approximately 90 patients suffering from depressive, anxious or adjustment disorders recruited from Spanish mental health settings will be randomised to receive 8 weekly 2 hours group sessions of ABCT, 8 weekly 2.5 hours group sessions of adapted MBSR (with no full-day silent retreat) or treatment as usual (TAU), with a 1:1:1 allocation rate. Patients in the ABCT and adapted MBSR groups will also receive TAU. The main outcome will be general affective distress measured by means of the 'Depression Anxiety Stress Scales-21' at post-test as primary endpoint. Other outcomes will be quality of life, mindfulness, self-compassion and the use of healthcare services. There will be a 6-month follow-up assessment. Intention-to-treat analysis will be conducted using linear mixed models. Per-protocol and secondary outcome analyses will be performed. A data monitoring committee comprising the trial manager, the ABCT and MBSR teachers and an independent clinical psychologist will monitor for possible negative side effects.

ETHICS AND DISSEMINATION

Approval was obtained from the Ethics Committee of the General University Hospital of Castellón, Spain. The results will be submitted to peer-reviewed specialised journals, and brief reports will be sent to participants on request.

TRIAL REGISTRATION NUMBER

NCT03425487.

Perseverative Cognition as an Explanatory Mechanism in the Relation Between Job Demands and Sleep Quality

Purpose

The aim of this longitudinal three-wave study was to examine (i) reciprocal associations among job demands, work-related perseverative cognition (PC), and sleep quality; (ii) PC as a mediator in-between job demands and sleep quality; and (iii) continuous high job demands in relation to sleep quality and work-related PC over time.

Method

A representative sample of the Swedish working population was approached in 2010, 2012, and 2014, and 2316 respondents were included in this longitudinal full-panel survey study. Structural equation modelling was performed to analyse the temporal relations between job demands, work-related PC, and sleep quality. Additionally, a subsample (N = 1149) consisting of individuals who reported the same level of exposure to job demands during all three waves (i.e. stable high, stable moderate, or stable low job demands) was examined in relation to PC and sleep quality over time.

Results

Analyses showed that job demands, PC, and poor sleep quality were positively and reciprocally related. Work-related PC mediated the normal and reversed, direct across-wave relations between job demands and sleep quality. Individuals with continuous high job demands reported significantly lower sleep quality and higher work-related PC, compared to individuals with continuous moderate/low job demands.

Conclusion

This study substantiated reciprocal relations between job demands, work-related PC, and sleep quality and supported work-related PC as an underlying mechanism of the reciprocal job demands-sleep relationship. Moreover, this study showed that chronically high job demands are a risk factor for low sleep quality.

Electronic supplementary material

The online version of this article (doi:10.1007/s12529-017-9683-y) contains supplementary material, which is available to authorized users.

Empirical Sample Size Guidelines for Use of Latent Difference Score Mediation

Mediation models are commonly used to identify the mechanisms through which one variable influences another. Among longitudinal mediation methods, latent difference score mediation stands out due to its unique ability to capture non-linear change over time. However, there is limited information regarding sample size demands to achieve adequate power with this method, resulting in few applications of latent difference score mediation. To address this limitation, the current study presents empirically supported sample size guidelines for 10 common latent difference score mediation structural models and 9 unique population models. The results of this study offer researchers with a set of representative sample estimates that may be used when designing studies or seeking funding.

Effects of Parenting Stress and Controlling Parenting Attitudes on Problem Behaviors of Preschool Children: Latent Growth Model Analysis

PURPOSE

This study was conducted to examine the longitudinal effects of parenting stress and parental control attitudes on problem behaviors in preschool children, using a latent growth model.

METHODS

Participants were 1,724 pairs of parents and 1,724 preschool children who had completed the panel survey on Korean children (5(th)~7(th) survey panels).

RESULTS

An analysis of the multivariate latent growth model of parenting stress, parental control attitudes, and children's problem behaviors suggested that the parents' intercepts for parenting stress influenced their intercepts for parental control attitudes (father: β=.21, p<.001; mother: β=.55, p<.001). In addition, the slopes for fathers' parenting stress was the only aspect that affected the slopes for mothers' parental control attitudes (β=.77, p<.001). Moreover, both the intercepts and slopes of parenting stress and parental control attitudes significantly affected the children's problem behaviors.

CONCLUSION

This study is significant as it provides longitudinal evidence of the impact of parenting stress and parental control attitudes on children's problem behaviors. The findings suggest that accurately assessing changes in parenting stress and parental control attitudes and developing intervention programs to reduce them will be effective in reducing problem behaviors in children.

Does work-personal life interference predict turnover among male and female managers, and do depressive symptoms mediate the association? A longitudinal study based on a Swedish cohort

BACKGROUND

In the present study we used a longitudinal design to examine if work-personal life interference predicted managerial turnover, if depressive symptoms mediated the association, and if the relationships differed by gender.

METHODS

Data were drawn from four waves (2010, 2012, 2014 and 2016) of the Swedish Longitudinal Occupational Survey of Health (SLOSH), a cohort of the Swedish working population. Participants who in any wave reported to have a managerial or other leading position were included (n = 717 men and 741 women). Autoregressive longitudinal mediation models within a multilevel structural equation modelling (MSEM) framework, in which repeated measures (level 1) were nested within individuals (level 2), were fitted to data. First, bivariate autoregressive and cross-lagged paths between the variables were fitted in gender stratified models. Secondly, a full gender stratified mediation model was built to estimate if the association between work-personal life interference and turnover was mediated through depressive symptoms. Gender differences in cross-lagged paths were estimated with multiple-group analysis. All analyses were adjusted for age, education, labour market sector, civil status and children living at home, and conducted in MPLUS 7.

RESULTS

In both genders there were significant paths between work-personal life interference and turnover. Depressive symptoms were, however, not found to mediate in the relationship between work-personal life interference and turnover. The models differed significantly between genders.

CONCLUSIONS

Establishing organisational prerequisites for good work-personal life balance among managers may be a means to retain both male and female managerial talent.

Tutorial: The practical application of longitudinal structural equation mediation models in clinical trials

The study of mediation of treatment effects, or how treatments work, is important to understanding and improving psychological and behavioral treatments, but applications often focus on mediators and outcomes measured at a single time point. Such cross-sectional analyses do not respect the implied temporal ordering that mediation suggests. Clinical trials of treatments often provide repeated measures of outcomes and, increasingly, of mediators as well. Repeated measurements allow the application of various types of longitudinal structural equation mediation models. These provide flexibility in modeling, including the ability to incorporate some types of measurement error and unmeasured confounding that can strengthen the robustness of findings. The usual approach is to identify the most theoretically plausible model and apply that model. In the absence of clear theory, we put forward the option of fitting a few theoretically plausible models, providing a type of sensitivity analysis for the mediation hypothesis. In this tutorial, we outline how to fit several longitudinal mediation models, including simplex, latent growth and latent change models. This will allow readers to learn about one type of model that is of interest, or about several alternative models, so that they can take this sensitivity approach. We use the Pacing, Graded Activity, and Cognitive Behavioral Therapy: A Randomized Evaluation (PACE) trial of rehabilitative treatments for chronic fatigue syndrome (ISRCTN 54285094) as a motivating example and describe how to fit and interpret various longitudinal mediation models using simulated data similar to those in the PACE trial. The simulated data set and Mplus code and output are provided. (PsycINFO Database Record

Well-Being and Arthritis Incidence: The Role of Inflammatory Mechanisms. Findings From the English Longitudinal Study of Ageing

OBJECTIVE

Higher levels of well-being are associated with lower levels of inflammatory markers in healthy populations; however, it is unclear whether this association translates into a reduced risk of disease. In the current study, we tested whether the association between well-being and inflammation results in a lower risk of arthritis.

METHODS

The sample consisted of 5266 participants 50 years or older from the English Longitudinal Study of Ageing and included six waves of data collection. We used a structural equation modeling approach to test whether inflammatory markers (C-reactive protein [CRP] or fibrinogen) mediated the association between well-being and arthritis risk for a 10-year follow-up period.

RESULTS

Higher levels of well-being were associated with a decrease in arthritis risk (hazard ratio = 0.97 per unit, 95% confidence interval = 0.96 to 0.98, p < .001). Of the two inflammatory markers, only CRP was associated with arthritis risk. Mediation analysis revealed that the indirect effect of well-being (at wave 1) on arthritis risk via CRP (at wave 2) was significant (hazard ratio = 0.996, 95% confidence interval = 0.995 to 0.998, p < .001). This effect remained significant after adjustment for demographic and health behavior variables and depressive symptoms.

CONCLUSIONS

CRP accounts for a small proportion of the association between well-being and a reduced risk of arthritis.

Mediators of a physical activity intervention among women with a family history of breast cancer

The current study examined mediators of an efficacious physical activity intervention. Women with a mean age of 42.6 (range 23-61) years and a family history of breast cancer were randomized to either an Internet-based physical activity intervention (n = 28) or an active control condition (n = 27) for three months. Data were collected between November 2010 and August 2011. Hypothesized mediators were examined using a product of coefficients model with bootstrapped standard errors. Significant mediation was observed for both self-efficacy and behavioral processes. Specifically, the regression coefficients of the indirect effects ("ab path": unstandardized effect of the intervention on physical activity that occurred through the mediator) were ab = 38.58 (95% confidence interval [CI]: 8.66-92.76) for self-efficacy, and ab = 42.02 (95% CI: 6.76-104.84) for behavioral processes. Other factors examined in this study, including cognitive processes, decisional balance, and perceived risk of breast cancer, were not statistically significant mediators. Findings suggest that self-efficacy and behavioral processes may be key constructs to use in targeting future physical activity interventions among women with a family history of breast cancer.

Do intrapersonal factors mediate the association of social support with physical activity in young women living in socioeconomically disadvantaged neighbourhoods? A longitudinal mediation analysis

Background

Levels of physical activity (PA) decrease when transitioning from adolescence into young adulthood. Evidence suggests that social support and intrapersonal factors (self-efficacy, outcome expectations, PA enjoyment) are associated with PA. The aim of the present study was to explore whether cross-sectional and longitudinal associations of social support from family and friends with leisure-time PA (LTPA) among young women living in disadvantaged areas were mediated by intrapersonal factors (PA enjoyment, outcome expectations, self-efficacy).

Methods

Survey data were collected from 18–30 year-old women living in disadvantaged suburbs of Victoria, Australia as part of the READI study in 2007–2008 (T0, N = 1197), with follow-up data collected in 2010–2011 (T1, N = 357) and 2012–2013 (T2, N = 271). A series of single-mediator models were tested using baseline (T0) and longitudinal data from all three time points with residual change scores for changes between measurements.

Results

Cross-sectional analyses showed that social support was associated with LTPA both directly and indirectly, mediated by intrapersonal factors. Each intrapersonal factor explained between 5.9–37.5% of the associations. None of the intrapersonal factors were significant mediators in the longitudinal analyses.

Conclusions

Results from the cross-sectional analyses suggest that the associations of social support from family and from friends with LTPA are mediated by intrapersonal factors (PA enjoyment, outcome expectations and self-efficacy). However, longitudinal analyses did not confirm these findings.

Prospective Relations among Low-Income African American Adolescents' Maternal Attachment Security, Self-Worth, and Risk Behaviors

This study examined prospective mediating relations among mother-adolescent attachment security, self-worth, and risk behaviors, including substance use and violence, across ages 13-17 in a sample of 901 low-income African American adolescents. Path analyses revealed that self-worth was a significant mediator between attachment security and risk behaviors, such that earlier attachment security predicted self-worth 1 year later, which in turn, predicted substance use, weapon carrying, and fighting in the 3rd year. Implications for the role of the secure base concept within the context of urban poverty are discussed.

Efficacy of "Attachment-Based Compassion Therapy" in the Treatment of Fibromyalgia: A Randomized Controlled Trial

OBJECTIVE

There is a growing interest in evaluating the effectiveness of compassion interventions for treating psychological disorders. The present study evaluated the effectiveness of "attachment-based compassion therapy" (ABCT) in the treatment of fibromyalgia (FM), and the role of psychological flexibility as a mediator of improvements.

METHODS

A total of 42 patients with FM were randomly assigned to ABCT or relaxation (active control group). Both the intervention and control condition were combined with treatment as usual (TAU). The primary outcome was functional status (FIQ), and the secondary outcomes were clinical severity (CGI-S), pain catastrophizing (PCS), anxiety (HADS-A), depression (HADS-D), quality of life (EQ-5D), and psychological flexibility (AAQ-II). Differences between the groups were estimated using mixed-effects models, and mediation assessments were conducted using path analyses.

RESULTS

The ABCT group demonstrated superior outcomes compared to the relaxation group, including better FIQ values after treatment (B = -3.01; p = 0.003). Differences in FIQ were maintained at 3-month follow-up (B = -3.33; p = 0.001). The absolute risk reduction in ABCT compared to relaxation increased by 40.0%, with an NNT = 3 based on criteria of ≥50% FIQ reduction after treatment. Psychological flexibility had a significant mediating effect on improvements.

CONCLUSION

These results suggest that ABCT combined with TAU appears to be effective in the treatment of FM symptoms.

CLINICAL TRIAL REGISTRATION

http://ClinicalTrials.gov, identifier NCT02454244.

Longitudinal Mediation Modeling of Unhealthy Behaviors as Mediators between Workplace Demands/Support and Depressive Symptoms

Lifestyle has been regarded as a key pathway through which adverse psychosocial working characteristics can give rise to long-term health problems. The purpose of this study was to estimate the indirect/mediated effect of health behaviors in the longitudinal work characteristics-depression relationship. The analyses were based on the Swedish Longitudinal Occupational Survey of Health, including 3706 working participants with repeat survey measures on four occasions (2008, 2010, 2012 and 2014). Psychosocial work characteristics including demands and social support were analyzed in relation to depressive symptoms. Autoregressive longitudinal mediation models using structural equation modeling were used to estimate the intermediate effects of unhealthy behaviors including current smoking, excessive alcohol consumption, unhealthy diet and physical inactivity. Both workplace demands and social support were related to later depressive symptoms. In bivariate models we found no significant paths from workplace demands to health behaviors, but two out of three significant time-specific paths from workplace support to excessive drinking and from excessive drinking to depressive symptoms. Social support was also associated with subsequent unhealthy diet, and one path from unhealthy diet to depressive symptoms was found. However, despite indications of certain longitudinal relationships between psychosocial working conditions and health behaviors as well as between health behaviors and depressive symptoms, no significant intermediate effects were found (p>0.05). We conclude that changes in unhealthy behaviors over a period of two years are unlikely to act as strong intermediaries in the longitudinal relationship between job demands and depressive symptoms and between social support and depressive symptoms.

Two distinct mediated pathways to disordered eating in response to weight stigmatization and their application to prevention programs

OBJECTIVE

Disordered eating behaviors among undergraduate women are common and, thus, are an important public health concern. Weight stigmatization, stress, and social withdrawal are often associated with disordered eating behaviors; however, it is unclear whether stress and social withdrawal act as mediators between weight stigmatization and disordered eating. By testing specific pathways to disordered eating, theory-driven prevention programs can be implemented.

METHODS

Self-reported surveys were administered to 217 undergraduate women during the Fall 2014 semester.

RESULTS

There were 2 distinct mediational pathways in response to weight stigmatization. Stress partially mediated the path between weight stigmatization and emotional eating (38%), whereas social withdrawal partially mediated the path between weight stigmatization and dietary restraint (44%).

CONCLUSIONS

Stress and social withdrawal mediate the relationship between weight stigmatization and disordered eating. The results of this study identified potentially critical risk factors that, if addressed, may improve outcomes of campus-based disordered eating programs for women.

Nocebo responses to high-voltage power lines: Evidence from a prospective field study

BACKGROUND

Experimental studies suggest that nocebo responses might occur after exposure to equipment emitting electromagnetic fields such as high voltage power lines (HVPLs) or mobile phone base stations.

OBJECTIVES

The present study investigates to what extent health responses to a new HVPL can be explained by beliefs of residents regarding the health effects of HVPLs.

METHODS

We used a quasi-experimental prospective field study design with two pretests during the construction of a new HVPL, and two posttests after it has been put into operation. Residents living near (0-300 m, n=229; 300-500 m, n=489) and farther away (500-2000 m, n=536) filled out questionnaires about their health and their beliefs about the negative health effects of power lines. Longitudinal mediation models were applied to investigate to what extent these beliefs could explain a change in reported symptoms after the new line was put into operation.

RESULTS

Significant (p<.01) indirect effects were found for proximity on the increase in reported cognitive (R(2)=0.41) and somatic (R(2)=0.79) symptoms after the power line was put into operation through an increase in the belief that power lines causes health effects. The direct effects of proximity on an increase in reported symptoms were not significant.

CONCLUSIONS

Our findings suggest that increases in reported health complaints after a new HVPL has been put into operation can be explained by nocebo mechanisms. Future field studies are needed to know whether our findings extend to other environmental health issues in a community.

Association between Self-Weighing and Percent Weight Change: Mediation Effects of Adherence to Energy Intake and Expenditure Goals

BACKGROUND

To date, no investigators have examined electronically recorded self-weighing behavior beyond 9 months or the underlying mechanisms of how self-weighing might impact weight change.

OBJECTIVE

Our aims were to examine electronically recorded self-weighing behavior in a weight-loss study and examine the possible mediating effects of adherence to energy intake and energy expenditure (EE) goals on the association between self-weighing and weight change.

DESIGN

This was a secondary analysis of the self-efficacy enhancement arm of the Self Efficacy Lifestyle Focus (SELF) trial, an 18-month randomized clinical trial.

PARTICIPANTS/SETTING

The study was conducted at the University of Pittsburgh (2008-2013). Overweight or obese adults with at least one additional cardiovascular risk factor were eligible.

INTERVENTION

Participants in the self-efficacy enhancement arm were given a scale (Carematix, Inc) and instructed to weigh themselves at least 3 days per week or every other day. The scale date- and time-stamped each weighing episode, storing up to 100 readings.

MAIN OUTCOME MEASURES

Weight was assessed every 6 months. Adherence to energy intake and EE goals was calculated on a weekly basis using paper diary data.

STATISTICAL ANALYSES PERFORMED

Linear mixed modeling and mediation analyses were used.

RESULTS

The sample (n=55) was 80% female, 69% non-Hispanic white, mean (standard deviation) age was 55.0 (9.6) years and body mass index (calculated as kg/m2) was 33.1 (3.7). Adherence to self-weighing declined over time (P<0.001). From baseline to 6 months, there was a significant mediation effect of adherence to energy intake (P=0.02) and EE goals (P=0.02) on the association between adherence to self-weighing and percent weight change. Mediation effects were not significant during the second and third 6-month periods of the study.

CONCLUSIONS

Objectively measured adherence to self-weighing declined over 18 months. During the first 6 months, self-weighing directly impacted weight change and indirectly impacted weight change through changes in energy intake and EE.

Psychosocial job conditions, fear avoidance beliefs and expected return to work following acute coronary syndrome: a cross-sectional study of fear-avoidance as a potential mediator

Background

Despite improvements in treatment, acute coronary syndrome remains a substantial cause for prolonged sick absences and premature retirement. Knowledge regarding what benefits return to work is limited, especially the effect of psychological processes and psychosocial work factors. The purposes of this cross-sectional study were two-fold: to examine associations between adverse psychosocial job conditions and fear-avoidance beliefs towards work, and to determine whether such beliefs mediated the relationship between work conditions and expected return to work in acute coronary syndrome survivors.

Methods

Study inclusion criteria: acute myocardial infarction or unstable angina diagnosis, below 65 years of age, being a resident in the West county of Sweden and currently working. In all, 509 individuals (21.8 % women) accepted study participation and for whom all data of study interest were available for analysis. Psychosocial work variables; job demand-control and effort-reward imbalance, were assessed with standard questionnaire batteries. Linear regression models were used to investigate relationships between psychosocial factors and fear-avoidance, and to evaluate mediator effects for fear-avoidance. Both total sample and gender stratified analyses were calculated.

Results

Fear-avoidance beliefs about work were associated to psychosocial job environments characterized by high strain (β 1.4; CI 1.2–1.6), active and passive work and high effort-reward imbalance (β 0.6; CI 0.5–0.7). Further, such beliefs also mediated the relationship between adverse work conditions and expected time for return to work. However, these results were only observed in total sample analyses or among or male participants. For women only high strain was linked to fear-avoidance, and these relationships became non-significant when entering chosen confounders.

Conclusions

This cross-sectional study showed that acute coronary syndrome survivors, who laboured under adverse psychosocial work conditions, held fear-avoidance beliefs towards their workplace. Furthermore, these beliefs mediated the relationships between - high strained or high effort-reward imbalanced work - and expected return to work. However, mentioned results were primarily found among men, which could results from few female study participants or gender differences in return to work mechanisms. Still, an earlier return to work might be promoted by interventions focusing on improved psychosocial work conditions and cognitive behavioural therapy targeting fear-avoidance beliefs.