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Internet-delivered cognitive behavioral therapy for adolescents with excessive worry: a randomized controlled trial with mediation analysis.

Wahlund, Tove ; Perrin, Sean LU orcid ; Lauri, Klara ; Burman, Malin ; Västhagen, Maja ; Jolstedt, Maral ; Nordh, Martina ; Serlachius, Eva LU ; Vigerland, Sarah and Andersson, Erik (2025) EABCT 2025 Congress
Abstract
Introduction: Excessive worry is common during adolescence and across a range of psychiatric conditions. There is a growing evidence base for the efficacy of cognitive behaviour therapy (CBT) in reducing the frequency of excessive worrying as a primary outcome in the context of clinical trials of youth with generalized anxiety disorder, and as a secondary outcome in trials of CBT for youth with obsessive compulsive, posttraumatic stress, and depressive disorders. Studies carried out with youth and adults find moderate to strong associations between Intolerance of Uncertainty (IU) and the frequency of worries. However, little is known about whether changes in IU mediate worry outcomes in CBT for youth. This study investigates whether: 1)... (More)
Introduction: Excessive worry is common during adolescence and across a range of psychiatric conditions. There is a growing evidence base for the efficacy of cognitive behaviour therapy (CBT) in reducing the frequency of excessive worrying as a primary outcome in the context of clinical trials of youth with generalized anxiety disorder, and as a secondary outcome in trials of CBT for youth with obsessive compulsive, posttraumatic stress, and depressive disorders. Studies carried out with youth and adults find moderate to strong associations between Intolerance of Uncertainty (IU) and the frequency of worries. However, little is known about whether changes in IU mediate worry outcomes in CBT for youth. This study investigates whether: 1) internet-delivered cognitive behavioral therapy (ICBT) focused on exposure to uncertainty is effective in reducing excessive worry; 2) improvements in worry are associated with reductions in other psychiatric symptoms; and 3) changes in intolerance of uncertainty (IU) mediates worry outcomes.
Methods: Adolescents (N= 62; aged 13-17 years) with excessive worry (>30 total score on Penn State Worry Questionnaire for Children (PSWQ-C) were randomly allocated to eight weeks of ICBT or a waitlist for ICBT (Waitlist). Self-reported worry (PSWQ-C; primary outcome) was measured weekly for 12 weeks and controlled effects assessed at week 12 post-baseline. IU and a comparator mediator (depression) were measured every other week for 12weeks during the treatment/waitlist phase.
Results: ICBT yielded significantly large reductions in worry compared to Waitlist (bootstrapped d=0.59). Worry reductions mediated improvements in anxiety and depression symptoms. However, changes in depression, but not IU, mediated worry outcomes.
Discussion: A brief course of worry-focused ICBT yielded moderate reductions in worry that were associated with improvements in anxiety and depression. Contrary to expectation, changes in IU did not explain worry reductions in this uncertainty- focused treatment but changes in depression did. These findings may reflect the brief IU scale used in this study.Alternatively, previous studies have found separate and strong relationships between low mood and the frequency and sense of control over worries. Low mood and IU are also related. Further studies are needed to identify change mechanisms in worry-focused treatments, including possible hierarchical or interactive relationships between worry, IU and mood. (Less)
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author
; ; ; ; ; ; ; ; and
organization
publishing date
type
Contribution to conference
publication status
published
subject
keywords
Internet Delivered CBT, Excessive worry, Generalized Anxiety Disorder, randomized controlled trial, Intolerance of Uncertainty, mediation analysis, Adolescents
conference name
EABCT 2025 Congress
conference location
Glasgow, United Kingdom
conference dates
2025-09-03 - 2025-09-06
project
Targeting excessive worry in adolescents using an online scalable intervention: A randomized controlled trial (Dnr 2020-03612)
language
English
LU publication?
yes
id
1ab993f4-9303-4b02-8fb5-d8d2cfde7b7b
date added to LUP
2026-02-18 10:50:37
date last changed
2026-02-18 11:17:12
@misc{1ab993f4-9303-4b02-8fb5-d8d2cfde7b7b,
  abstract     = {{Introduction: Excessive worry is common during adolescence and across a range of psychiatric conditions. There is a growing evidence base for the efficacy of cognitive behaviour therapy (CBT) in reducing the frequency of excessive worrying as a primary outcome in the context of clinical trials of youth with generalized anxiety disorder, and as a secondary outcome in trials of CBT for youth with obsessive compulsive, posttraumatic stress, and depressive disorders. Studies carried out with youth and adults find moderate to strong associations between Intolerance of Uncertainty (IU) and the frequency of worries. However, little is known about whether changes in IU mediate worry outcomes in CBT for youth. This study investigates whether: 1) internet-delivered cognitive behavioral therapy (ICBT) focused on exposure to uncertainty is effective in reducing excessive worry; 2) improvements in worry are associated with reductions in other psychiatric symptoms; and 3) changes in intolerance of uncertainty (IU) mediates worry outcomes.<br/>Methods: Adolescents (N= 62; aged 13-17 years) with excessive worry (&gt;30 total score on Penn State Worry Questionnaire for Children (PSWQ-C) were randomly allocated to eight weeks of ICBT or a waitlist for ICBT (Waitlist). Self-reported worry (PSWQ-C; primary outcome) was measured weekly for 12 weeks and controlled effects assessed at week 12 post-baseline. IU and a comparator mediator (depression) were measured every other week for 12weeks during the treatment/waitlist phase.<br/>Results: ICBT yielded significantly large reductions in worry compared to Waitlist (bootstrapped d=0.59). Worry reductions mediated improvements in anxiety and depression symptoms. However, changes in depression, but not IU, mediated worry outcomes. <br/>Discussion: A brief course of worry-focused ICBT yielded moderate reductions in worry that were associated with improvements in anxiety and depression. Contrary to expectation, changes in IU did not explain worry reductions in this uncertainty- focused treatment but changes in depression did. These findings may reflect the brief IU scale used in this study.Alternatively, previous studies have found separate and strong relationships between low mood and the frequency and sense of control over worries. Low mood and IU are also related. Further studies are needed to identify change mechanisms in worry-focused treatments, including possible hierarchical or interactive relationships between worry, IU and mood.}},
  author       = {{Wahlund, Tove and Perrin, Sean and Lauri, Klara and Burman, Malin and Västhagen, Maja and Jolstedt, Maral and Nordh, Martina and Serlachius, Eva and Vigerland, Sarah and Andersson, Erik}},
  keywords     = {{Internet Delivered CBT; Excessive worry; Generalized Anxiety Disorder; randomized controlled trial; Intolerance of Uncertainty; mediation analysis; Adolescents}},
  language     = {{eng}},
  month        = {{09}},
  title        = {{Internet-delivered cognitive behavioral therapy for adolescents with excessive worry: a randomized controlled trial with mediation analysis.}},
  url          = {{https://lup.lub.lu.se/search/files/242632361/Perrin_et_al_2025_-_iICBT_for_Adololescents_with_Excessive_Worry_-_EABCT2025_Poster.pdf}},
  year         = {{2025}},
}