Search

Previous studies have found an association between excessive worrying and negative beliefs about worry. It is unclear if change in these beliefs mediate worry reduction. This study aimed to examine (1) if a simplified online metacognitive intervention can reduce worry, (2) whether changes in negative beliefs about worry mediate changes in worry severity, and (3) moderated mediation, i.e., if the mediating effect is more pronounced in individuals with a high degree of negative beliefs about worry at baseline. Adult excessive worriers (N = 108) were randomized to 10-weeks of the online metacognitive intervention (MCI) aimed at reducing negative beliefs about worry, or to wait-list (WL). Outcomes, mediation, and moderated mediation were examined via growth curve modelling. Results indicated a significant reduction in the MCI group (d = 1.6). Reductions in negative beliefs about worry and depressive symptoms separately mediated changes in worry severity during the intervention, but in a multivariate test only the former remained significant. Sensitivity analysis indicated that the hypothesized mediation was robust to possible violations of mediator-outcome confounding. The moderated mediation hypothesis was not supported. The results from this randomized trial add to the growing literature suggesting that negative beliefs about worry play a key role in worry-related problems. ClinicalTrials.gov Identifier: NCT03393156, Funding Agencies|Fredrik and Ingrid Thuring foundation; Strategic Research Area Healthcare Science (SFO-V)

Previous studies have found an association between excessive worrying and negative beliefs about worry. It is unclear if change in these beliefs mediate worry reduction. This study aimed to examine (1) if a simplified online metacognitive intervention can reduce worry, (2) whether changes in negative beliefs about worry mediate changes in worry severity, and (3) moderated mediation, i.e., if the mediating effect is more pronounced in individuals with a high degree of negative beliefs about worry at baseline. Adult excessive worriers (N = 108) were randomized to 10-weeks of the online metacognitive intervention (MCI) aimed at reducing negative beliefs about worry, or to wait-list (WL). Outcomes, mediation, and moderated mediation were examined via growth curve modelling. Results indicated a significant reduction in the MCI group (d = 1.6). Reductions in negative beliefs about worry and depressive symptoms separately mediated changes in worry severity during the intervention, but in a multivariate test only the former remained significant. Sensitivity analysis indicated that the hypothesized mediation was robust to possible violations of mediator-outcome confounding. The moderated mediation hypothesis was not supported. The results from this randomized trial add to the growing literature suggesting that negative beliefs about worry play a key role in worry-related problems. ClinicalTrials.gov Identifier: NCT03393156, Funding Agencies|Fredrik and Ingrid Thuring foundation; Strategic Research Area Healthcare Science (SFO-V)

Previous studies have found an association between excessive worrying and negative beliefs about worry. It is unclear if change in these beliefs mediate worry reduction. This study aimed to examine (1) if a simplified online metacognitive intervention can reduce worry, (2) whether changes in negative beliefs about worry mediate changes in worry severity, and (3) moderated mediation, i.e., if the mediating effect is more pronounced in individuals with a high degree of negative beliefs about worry at baseline. Adult excessive worriers (N = 108) were randomized to 10-weeks of the online metacognitive intervention (MCI) aimed at reducing negative beliefs about worry, or to wait-list (WL). Outcomes, mediation, and moderated mediation were examined via growth curve modelling. Results indicated a significant reduction in the MCI group (d = 1.6). Reductions in negative beliefs about worry and depressive symptoms separately mediated changes in worry severity during the intervention, but in a multivariate test only the former remained significant. Sensitivity analysis indicated that the hypothesized mediation was robust to possible violations of mediator-outcome confounding. The moderated mediation hypothesis was not supported. The results from this randomized trial add to the growing literature suggesting that negative beliefs about worry play a key role in worry-related problems. ClinicalTrials.gov Identifier: NCT03393156, Funding Agencies|Fredrik and Ingrid Thuring foundation; Strategic Research Area Healthcare Science (SFO-V)

Previous studies have found an association between excessive worrying and negative beliefs about worry. It is unclear if change in these beliefs mediate worry reduction. This study aimed to examine (1) if a simplified online metacognitive intervention can reduce worry, (2) whether changes in negative beliefs about worry mediate changes in worry severity, and (3) moderated mediation, i.e., if the mediating effect is more pronounced in individuals with a high degree of negative beliefs about worry at baseline. Adult excessive worriers (N = 108) were randomized to 10-weeks of the online metacognitive intervention (MCI) aimed at reducing negative beliefs about worry, or to wait-list (WL). Outcomes, mediation, and moderated mediation were examined via growth curve modelling. Results indicated a significant reduction in the MCI group (d = 1.6). Reductions in negative beliefs about worry and depressive symptoms separately mediated changes in worry severity during the intervention, but in a multivariate test only the former remained significant. Sensitivity analysis indicated that the hypothesized mediation was robust to possible violations of mediator-outcome confounding. The moderated mediation hypothesis was not supported. The results from this randomized trial add to the growing literature suggesting that negative beliefs about worry play a key role in worry-related problems. ClinicalTrials.gov Identifier: NCT03393156, Funding Agencies|Fredrik and Ingrid Thuring foundation; Strategic Research Area Healthcare Science (SFO-V)

Previous studies have found an association between excessive worrying and negative beliefs about worry. It is unclear if change in these beliefs mediate worry reduction. This study aimed to examine (1) if a simplified online metacognitive intervention can reduce worry, (2) whether changes in negative beliefs about worry mediate changes in worry severity, and (3) moderated mediation, i.e., if the mediating effect is more pronounced in individuals with a high degree of negative beliefs about worry at baseline. Adult excessive worriers (N = 108) were randomized to 10-weeks of the online metacognitive intervention (MCI) aimed at reducing negative beliefs about worry, or to wait-list (WL). Outcomes, mediation, and moderated mediation were examined via growth curve modelling. Results indicated a significant reduction in the MCI group (d = 1.6). Reductions in negative beliefs about worry and depressive symptoms separately mediated changes in worry severity during the intervention, but in a multivariate test only the former remained significant. Sensitivity analysis indicated that the hypothesized mediation was robust to possible violations of mediator-outcome confounding. The moderated mediation hypothesis was not supported. The results from this randomized trial add to the growing literature suggesting that negative beliefs about worry play a key role in worry-related problems. ClinicalTrials.gov Identifier: NCT03393156, Funding Agencies|Fredrik and Ingrid Thuring foundation; Strategic Research Area Healthcare Science (SFO-V)

Previous studies have found an association between excessive worrying and negative beliefs about worry. It is unclear if change in these beliefs mediate worry reduction. This study aimed to examine (1) if a simplified online metacognitive intervention can reduce worry, (2) whether changes in negative beliefs about worry mediate changes in worry severity, and (3) moderated mediation, i.e., if the mediating effect is more pronounced in individuals with a high degree of negative beliefs about worry at baseline. Adult excessive worriers (N = 108) were randomized to 10-weeks of the online metacognitive intervention (MCI) aimed at reducing negative beliefs about worry, or to wait-list (WL). Outcomes, mediation, and moderated mediation were examined via growth curve modelling. Results indicated a significant reduction in the MCI group (d = 1.6). Reductions in negative beliefs about worry and depressive symptoms separately mediated changes in worry severity during the intervention, but in a multivariate test only the former remained significant. Sensitivity analysis indicated that the hypothesized mediation was robust to possible violations of mediator-outcome confounding. The moderated mediation hypothesis was not supported. The results from this randomized trial add to the growing literature suggesting that negative beliefs about worry play a key role in worry-related problems. ClinicalTrials.gov Identifier: NCT03393156, Funding Agencies|Fredrik and Ingrid Thuring foundation; Strategic Research Area Healthcare Science (SFO-V)

Past research has failed to identify consistent moderators of outcomes in psychological treatments for irritable bowel syndrome (IBS). The aim of this study was to test previously identified mediators as potential moderators of the effects of exposure therapy on IBS symptoms in a previously published randomized component trial. In total, 309 participants with IBS were randomized to internet-delivered cognitive behavioral treatment that included exposure (ICBT) or to the same treatment protocol without exposure (ICBT-WE) and were asked to report on gastrointestinal symptoms at pretreatment, posttreatment and weekly during the treatment. Pretreatment scores of The Visceral Sensitivity Index (VSI) and The Irritable Bowel Syndrome Behavioral Responses Questionnaire (IBS-BRQ) (i.e., gastrointestinal anxiety and avoidance behavior) were evaluated as predictors and moderators. Piecewise latent growth curve models were employed to evaluate moderators during distinct phases of the trial, prior to and following the onset of exposure in ICBT. Results revealed that pretreatment scores on IBS-BRQ (avoidance) moderated the effect of exposure therapy during the specific phase in which exposure was implemented in ICBT, with higher avoidance scores linked to stronger positive effects of exposure. VSI did not serve as predictor nor moderator. Adding exposure to CBT seems to be especially important for persons with moderate to high levels of avoidance behaviors in order to reduce gastrointestinal symptoms.

Background: Irritable bowel syndrome (IBS) is a debilitating and costly disorder. Cognitive behavior therapy (CBT) is effective in the treatment of IBS, both when delivered over the internet and in face-to-face settings. CBT consists of different components and little is known about their relative importance. We have in an earlier study showed that inclusion of exposure in the CBT for IBS makes it even more effective. In the present study we wanted to evaluate the economic effects for society of inclusion vs exclusion of exposure in an internet delivered CBT for IBS. Methods: We used data from a previous study with 309 participants with IBS. Participants were randomized to internet delivered CBT with (ICBT) or without exposure (ICBT-WE). We compared direct and indirect costs at baseline, after treatment, and 6 months after treatment (primary endpoint; 6MFU). Data was also collected on symptom severity and time spent by therapists and participants. The relative Incremental Cost Effectiveness Ratio (ICER) was calculated for the two treatment conditions and the return on investment (ROI). Results: Results showed that ICBT cost $213.5 (20%) more than ICBT-WE per participant. However, ICBT was associated with larger reductions regarding both costs and symptoms than ICBT-WE at 6MFU. The ICER was - 301.69, meaning that for every point improvement on the Gastrointestinal Symptom Rating Scale-IBS version in ICBT, societal costs would be reduced with approximately $300. At a willingness to pay for a case of clinically significant improvement in IBS symptoms of $0, there was an 84% probability of cost-effectiveness. ROI analysis showed that for every $1 invested in ICBT rather than ICBT-WE, the return would be $5.64 six months after treatment. Analyses of post-treatment data showed a similar pattern although cost-savings were smaller. Conclusions: Including exposure in Cognitive Behavior Treatment for IBS is more cost-effective from a societal perspective than not including it, Funding Agencies|Karolinska InstituteKarolinska Institutet; Region Vastra Gotaland, Sweden

Background: Irritable bowel syndrome (IBS) is a debilitating and costly disorder. Cognitive behavior therapy (CBT) is effective in the treatment of IBS, both when delivered over the internet and in face-to-face settings. CBT consists of different components and little is known about their relative importance. We have in an earlier study showed that inclusion of exposure in the CBT for IBS makes it even more effective. In the present study we wanted to evaluate the economic effects for society of inclusion vs exclusion of exposure in an internet delivered CBT for IBS. Methods: We used data from a previous study with 309 participants with IBS. Participants were randomized to internet delivered CBT with (ICBT) or without exposure (ICBT-WE). We compared direct and indirect costs at baseline, after treatment, and 6 months after treatment (primary endpoint; 6MFU). Data was also collected on symptom severity and time spent by therapists and participants. The relative Incremental Cost Effectiveness Ratio (ICER) was calculated for the two treatment conditions and the return on investment (ROI). Results: Results showed that ICBT cost $213.5 (20%) more than ICBT-WE per participant. However, ICBT was associated with larger reductions regarding both costs and symptoms than ICBT-WE at 6MFU. The ICER was - 301.69, meaning that for every point improvement on the Gastrointestinal Symptom Rating Scale-IBS version in ICBT, societal costs would be reduced with approximately $300. At a willingness to pay for a case of clinically significant improvement in IBS symptoms of $0, there was an 84% probability of cost-effectiveness. ROI analysis showed that for every $1 invested in ICBT rather than ICBT-WE, the return would be $5.64 six months after treatment. Analyses of post-treatment data showed a similar pattern although cost-savings were smaller. Conclusions: Including exposure in Cognitive Behavior Treatment for IBS is more cost-effective from a societal perspective than not including it, Funding Agencies|Karolinska InstituteKarolinska Institutet; Region Vastra Gotaland, Sweden

Past research has failed to identify consistent moderators of outcomes in psychological treatments for irritable bowel syndrome (IBS). The aim of this study was to test previously identified mediators as potential moderators of the effects of exposure therapy on IBS symptoms in a previously published randomized component trial. In total, 309 participants with IBS were randomized to internet-delivered cognitive behavioral treatment that included exposure (ICBT) or to the same treatment protocol without exposure (ICBT-WE) and were asked to report on gastrointestinal symptoms at pretreatment, posttreatment and weekly during the treatment. Pretreatment scores of The Visceral Sensitivity Index (VSI) and The Irritable Bowel Syndrome Behavioral Responses Questionnaire (IBS-BRQ) (i.e., gastrointestinal anxiety and avoidance behavior) were evaluated as predictors and moderators. Piecewise latent growth curve models were employed to evaluate moderators during distinct phases of the trial, prior to and following the onset of exposure in ICBT. Results revealed that pretreatment scores on IBS-BRQ (avoidance) moderated the effect of exposure therapy during the specific phase in which exposure was implemented in ICBT, with higher avoidance scores linked to stronger positive effects of exposure. VSI did not serve as predictor nor moderator. Adding exposure to CBT seems to be especially important for persons with moderate to high levels of avoidance behaviors in order to reduce gastrointestinal symptoms.

Background: Irritable bowel syndrome (IBS) is a debilitating and costly disorder. Cognitive behavior therapy (CBT) is effective in the treatment of IBS, both when delivered over the internet and in face-to-face settings. CBT consists of different components and little is known about their relative importance. We have in an earlier study showed that inclusion of exposure in the CBT for IBS makes it even more effective. In the present study we wanted to evaluate the economic effects for society of inclusion vs exclusion of exposure in an internet delivered CBT for IBS. Methods: We used data from a previous study with 309 participants with IBS. Participants were randomized to internet delivered CBT with (ICBT) or without exposure (ICBT-WE). We compared direct and indirect costs at baseline, after treatment, and 6 months after treatment (primary endpoint; 6MFU). Data was also collected on symptom severity and time spent by therapists and participants. The relative Incremental Cost Effectiveness Ratio (ICER) was calculated for the two treatment conditions and the return on investment (ROI). Results: Results showed that ICBT cost $213.5 (20%) more than ICBT-WE per participant. However, ICBT was associated with larger reductions regarding both costs and symptoms than ICBT-WE at 6MFU. The ICER was - 301.69, meaning that for every point improvement on the Gastrointestinal Symptom Rating Scale-IBS version in ICBT, societal costs would be reduced with approximately $300. At a willingness to pay for a case of clinically significant improvement in IBS symptoms of $0, there was an 84% probability of cost-effectiveness. ROI analysis showed that for every $1 invested in ICBT rather than ICBT-WE, the return would be $5.64 six months after treatment. Analyses of post-treatment data showed a similar pattern although cost-savings were smaller. Conclusions: Including exposure in Cognitive Behavior Treatment for IBS is more cost-effective from a societal perspective than not including it, Funding Agencies|Karolinska InstituteKarolinska Institutet; Region Vastra Gotaland, Sweden

Past research has failed to identify consistent moderators of outcomes in psychological treatments for irritable bowel syndrome (IBS). The aim of this study was to test previously identified mediators as potential moderators of the effects of exposure therapy on IBS symptoms in a previously published randomized component trial. In total, 309 participants with IBS were randomized to internet-delivered cognitive behavioral treatment that included exposure (ICBT) or to the same treatment protocol without exposure (ICBT-WE) and were asked to report on gastrointestinal symptoms at pretreatment, posttreatment and weekly during the treatment. Pretreatment scores of The Visceral Sensitivity Index (VSI) and The Irritable Bowel Syndrome Behavioral Responses Questionnaire (IBS-BRQ) (i.e., gastrointestinal anxiety and avoidance behavior) were evaluated as predictors and moderators. Piecewise latent growth curve models were employed to evaluate moderators during distinct phases of the trial, prior to and following the onset of exposure in ICBT. Results revealed that pretreatment scores on IBS-BRQ (avoidance) moderated the effect of exposure therapy during the specific phase in which exposure was implemented in ICBT, with higher avoidance scores linked to stronger positive effects of exposure. VSI did not serve as predictor nor moderator. Adding exposure to CBT seems to be especially important for persons with moderate to high levels of avoidance behaviors in order to reduce gastrointestinal symptoms.

Past research has failed to identify consistent moderators of outcomes in psychological treatments for irritable bowel syndrome (IBS). The aim of this study was to test previously identified mediators as potential moderators of the effects of exposure therapy on IBS symptoms in a previously published randomized component trial. In total, 309 participants with IBS were randomized to internet-delivered cognitive behavioral treatment that included exposure (ICBT) or to the same treatment protocol without exposure (ICBT-WE) and were asked to report on gastrointestinal symptoms at pretreatment, posttreatment and weekly during the treatment. Pretreatment scores of The Visceral Sensitivity Index (VSI) and The Irritable Bowel Syndrome Behavioral Responses Questionnaire (IBS-BRQ) (i.e., gastrointestinal anxiety and avoidance behavior) were evaluated as predictors and moderators. Piecewise latent growth curve models were employed to evaluate moderators during distinct phases of the trial, prior to and following the onset of exposure in ICBT. Results revealed that pretreatment scores on IBS-BRQ (avoidance) moderated the effect of exposure therapy during the specific phase in which exposure was implemented in ICBT, with higher avoidance scores linked to stronger positive effects of exposure. VSI did not serve as predictor nor moderator. Adding exposure to CBT seems to be especially important for persons with moderate to high levels of avoidance behaviors in order to reduce gastrointestinal symptoms.

Background: Irritable bowel syndrome (IBS) is a debilitating and costly disorder. Cognitive behavior therapy (CBT) is effective in the treatment of IBS, both when delivered over the internet and in face-to-face settings. CBT consists of different components and little is known about their relative importance. We have in an earlier study showed that inclusion of exposure in the CBT for IBS makes it even more effective. In the present study we wanted to evaluate the economic effects for society of inclusion vs exclusion of exposure in an internet delivered CBT for IBS. Methods: We used data from a previous study with 309 participants with IBS. Participants were randomized to internet delivered CBT with (ICBT) or without exposure (ICBT-WE). We compared direct and indirect costs at baseline, after treatment, and 6 months after treatment (primary endpoint; 6MFU). Data was also collected on symptom severity and time spent by therapists and participants. The relative Incremental Cost Effectiveness Ratio (ICER) was calculated for the two treatment conditions and the return on investment (ROI). Results: Results showed that ICBT cost $213.5 (20%) more than ICBT-WE per participant. However, ICBT was associated with larger reductions regarding both costs and symptoms than ICBT-WE at 6MFU. The ICER was - 301.69, meaning that for every point improvement on the Gastrointestinal Symptom Rating Scale-IBS version in ICBT, societal costs would be reduced with approximately $300. At a willingness to pay for a case of clinically significant improvement in IBS symptoms of $0, there was an 84% probability of cost-effectiveness. ROI analysis showed that for every $1 invested in ICBT rather than ICBT-WE, the return would be $5.64 six months after treatment. Analyses of post-treatment data showed a similar pattern although cost-savings were smaller. Conclusions: Including exposure in Cognitive Behavior Treatment for IBS is more cost-effective from a societal perspective than not including it, Funding Agencies|Karolinska InstituteKarolinska Institutet; Region Vastra Gotaland, Sweden

Background: Irritable bowel syndrome (IBS) is a debilitating and costly disorder. Cognitive behavior therapy (CBT) is effective in the treatment of IBS, both when delivered over the internet and in face-to-face settings. CBT consists of different components and little is known about their relative importance. We have in an earlier study showed that inclusion of exposure in the CBT for IBS makes it even more effective. In the present study we wanted to evaluate the economic effects for society of inclusion vs exclusion of exposure in an internet delivered CBT for IBS. Methods: We used data from a previous study with 309 participants with IBS. Participants were randomized to internet delivered CBT with (ICBT) or without exposure (ICBT-WE). We compared direct and indirect costs at baseline, after treatment, and 6 months after treatment (primary endpoint; 6MFU). Data was also collected on symptom severity and time spent by therapists and participants. The relative Incremental Cost Effectiveness Ratio (ICER) was calculated for the two treatment conditions and the return on investment (ROI). Results: Results showed that ICBT cost $213.5 (20%) more than ICBT-WE per participant. However, ICBT was associated with larger reductions regarding both costs and symptoms than ICBT-WE at 6MFU. The ICER was - 301.69, meaning that for every point improvement on the Gastrointestinal Symptom Rating Scale-IBS version in ICBT, societal costs would be reduced with approximately $300. At a willingness to pay for a case of clinically significant improvement in IBS symptoms of $0, there was an 84% probability of cost-effectiveness. ROI analysis showed that for every $1 invested in ICBT rather than ICBT-WE, the return would be $5.64 six months after treatment. Analyses of post-treatment data showed a similar pattern although cost-savings were smaller. Conclusions: Including exposure in Cognitive Behavior Treatment for IBS is more cost-effective from a societal perspective than not including it, Funding Agencies|Karolinska InstituteKarolinska Institutet; Region Vastra Gotaland, Sweden

Past research has failed to identify consistent moderators of outcomes in psychological treatments for irritable bowel syndrome (IBS). The aim of this study was to test previously identified mediators as potential moderators of the effects of exposure therapy on IBS symptoms in a previously published randomized component trial. In total, 309 participants with IBS were randomized to internet-delivered cognitive behavioral treatment that included exposure (ICBT) or to the same treatment protocol without exposure (ICBT-WE) and were asked to report on gastrointestinal symptoms at pretreatment, posttreatment and weekly during the treatment. Pretreatment scores of The Visceral Sensitivity Index (VSI) and The Irritable Bowel Syndrome Behavioral Responses Questionnaire (IBS-BRQ) (i.e., gastrointestinal anxiety and avoidance behavior) were evaluated as predictors and moderators. Piecewise latent growth curve models were employed to evaluate moderators during distinct phases of the trial, prior to and following the onset of exposure in ICBT. Results revealed that pretreatment scores on IBS-BRQ (avoidance) moderated the effect of exposure therapy during the specific phase in which exposure was implemented in ICBT, with higher avoidance scores linked to stronger positive effects of exposure. VSI did not serve as predictor nor moderator. Adding exposure to CBT seems to be especially important for persons with moderate to high levels of avoidance behaviors in order to reduce gastrointestinal symptoms.

Background: Irritable bowel syndrome (IBS) is a debilitating and costly disorder. Cognitive behavior therapy (CBT) is effective in the treatment of IBS, both when delivered over the internet and in face-to-face settings. CBT consists of different components and little is known about their relative importance. We have in an earlier study showed that inclusion of exposure in the CBT for IBS makes it even more effective. In the present study we wanted to evaluate the economic effects for society of inclusion vs exclusion of exposure in an internet delivered CBT for IBS. Methods: We used data from a previous study with 309 participants with IBS. Participants were randomized to internet delivered CBT with (ICBT) or without exposure (ICBT-WE). We compared direct and indirect costs at baseline, after treatment, and 6 months after treatment (primary endpoint; 6MFU). Data was also collected on symptom severity and time spent by therapists and participants. The relative Incremental Cost Effectiveness Ratio (ICER) was calculated for the two treatment conditions and the return on investment (ROI). Results: Results showed that ICBT cost $213.5 (20%) more than ICBT-WE per participant. However, ICBT was associated with larger reductions regarding both costs and symptoms than ICBT-WE at 6MFU. The ICER was - 301.69, meaning that for every point improvement on the Gastrointestinal Symptom Rating Scale-IBS version in ICBT, societal costs would be reduced with approximately $300. At a willingness to pay for a case of clinically significant improvement in IBS symptoms of $0, there was an 84% probability of cost-effectiveness. ROI analysis showed that for every $1 invested in ICBT rather than ICBT-WE, the return would be $5.64 six months after treatment. Analyses of post-treatment data showed a similar pattern although cost-savings were smaller. Conclusions: Including exposure in Cognitive Behavior Treatment for IBS is more cost-effective from a societal perspective than not including it, Funding Agencies|Karolinska InstituteKarolinska Institutet; Region Vastra Gotaland, Sweden

Past research has failed to identify consistent moderators of outcomes in psychological treatments for irritable bowel syndrome (IBS). The aim of this study was to test previously identified mediators as potential moderators of the effects of exposure therapy on IBS symptoms in a previously published randomized component trial. In total, 309 participants with IBS were randomized to internet-delivered cognitive behavioral treatment that included exposure (ICBT) or to the same treatment protocol without exposure (ICBT-WE) and were asked to report on gastrointestinal symptoms at pretreatment, posttreatment and weekly during the treatment. Pretreatment scores of The Visceral Sensitivity Index (VSI) and The Irritable Bowel Syndrome Behavioral Responses Questionnaire (IBS-BRQ) (i.e., gastrointestinal anxiety and avoidance behavior) were evaluated as predictors and moderators. Piecewise latent growth curve models were employed to evaluate moderators during distinct phases of the trial, prior to and following the onset of exposure in ICBT. Results revealed that pretreatment scores on IBS-BRQ (avoidance) moderated the effect of exposure therapy during the specific phase in which exposure was implemented in ICBT, with higher avoidance scores linked to stronger positive effects of exposure. VSI did not serve as predictor nor moderator. Adding exposure to CBT seems to be especially important for persons with moderate to high levels of avoidance behaviors in order to reduce gastrointestinal symptoms.

Objective: Systematic exposure is potentially an effective treatment procedure for treating irritable bowel syndrome (IBS), but little is known about the processes by which it achieves its effect on outcome. The aim of this study was to identify mediators in a previously published randomized dismantling trial in which participants with IBS were randomized to Internet-delivered cognitive-behavioral treatment (ICBT) that incorporated systematic exposure or to the same treatment protocol without exposure (ICBT-WE). Method: Weekly measurements of gastrointestinal anxiety-specific process variables (behavioral avoidance, gastrointestinal-specific anxiety) based on the gastrointestinal symptom-specific anxiety model, generic process variables (self-efficacy and mindful nonreactivity), and treatment outcome (IBS symptoms) were obtained from 309 participants with IBS. Growth models and cross-lagged panel models, estimated within structural equation modeling, were employed to evaluate mediators of outcome. Results: Parallel process growth modeling showed that behavioral avoidance, gastrointestinal-specific anxiety, self-efficacy mediated the incremental effect of ICBT compared to ICBT-WE. The mediated effect of avoidance was stronger for individuals scoring high on the avoidance variable at 1st measurement point. Cross-lagged regression analyses with random effects revealed that behavioral avoidance and gastrointestinal-specific anxiety had a stronger effect on subsequent symptom change rather than vice versa, whereas mindful nonreactivity and self-efficacy displayed the opposite pattern. Conclusions: The evidence collectively provided support for the hypothesis that exposure for IBS achieves its positive results by virtue of changing gastrointestinal anxiety-specific processes rather than generic processes. IBS-specific behavioral avoidance emerged as the most clear-cut mediator of the specific effect of exposure on outcome.