| Original language | English |
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| Article number | 104224 |
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| Journal | Behaviour Research and Therapy |
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| Volume | 159 |
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| Early online date | 12 Nov 2022 |
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| DOIs | |
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| Accepted/In press | 29 Oct 2022 |
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| E-pub ahead of print | 12 Nov 2022 |
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| Published | Dec 2022 |
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| Additional links | |
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Funding Information:
The study was funded by Guy's and St. Thomas' Charity.
Funding Information:
TC, SL, KG and RMM acknowledge that this paper represents independent research part-funded by the National Institute for Health Research (NIHR) Biomedical Research Centre at South London and Maudsley NHS Foundation Trust , King's College London and the NIHR Applied Research Collaboration South London (NIHR ARC South London) at King's College Hospital NHS Foundation Trust . The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health and Social Care.
Publisher Copyright:
© 2022 The Authors
The PRINCE secondary trial did not find any evidence that transdiagnostic cognitive behavioural therapy (TDT-CBT) plus standard medical care (SMC) was more efficacious than SMC for patients with Persistent Physical Symptoms (PPS) for the primary outcome Work and Social Adjustment Scale (WSAS) at final follow-up (52 weeks). There was a significant treatment effect for TDT-CBT plus CBT compared with SMC for two secondary outcomes: WSAS at the end of active treatment (20 weeks) and symptom severity (Patient Health Questionnaire, PHQ-15) at 52 weeks.
To understand mechanisms that lead to effects of TDT-CBT plus SMC versus SMC we performed a planned secondary mediation analysis. We investigated whether TDT-CBT treatment effects on these two secondary outcomes at the end of the treatment could be explained by effects on variables that were targeted by TDT-CBT during the initial phase of treatment. We pre-specified mediator variables measured at mid-treatment (9 weeks).
Reductions in catastrophising and symptom focusing were the strongest mediators of TDT-CBT treatment effects on WSAS at the end of treatment. Improvements in symptom focusing also mediated the effect of TDT-CBT on PHQ-15.
Future developments of the TDT-CBT intervention could benefit from targeting these mediators.