Rumination, also known as repetitive thought, is prolonged and recurrent negative thinking about feelings and upsetting past experiences (Watkins, 2008). In contrast, worry refers to a chain of thoughts and negative feelings about anticipated future events (Borkovec, 1983). Closely aligned, rumination and worry are considered transdiagnostic, which means they are factors associated with numerous mental health difficulties (McEvoy et al., 2013; Zagaria et al., 2023).
One of the detrimental effects of repetitive negative thinking is that it also magnifies and prolongs negative mood states, interferes with problem solving and the ability to make positive behaviour changes (Watkins & Roberts, 2020). As such, it makes sense that some mental health interventions focus on transdiagnostic factors like repetitive negative thinking, because targeting this could have a widespread impact.
The last Mental Elf blog that focused on repetitive negative thinking in young people was published in 2017 – so what has changed since? For this blog, I have looked at a systematic review and meta-analysis by Egan and colleagues (2024) which focused on worry and rumination as the target for interventions for young people experiencing a range of mental health difficulties.
Rumination and worry can have a negative impact across a range of mental health difficulties, making them a potential target for transdiagnostic intervention.
Methods
One of the highlights of this systematic review and meta-analysis was that it was co-produced with an international group of young people with lived experience of anxiety, depression, and psychosis. The young people, who were supported by lived experience leads, guided all aspects of the research, including the development of the search strategies, the protocol, synthesising insights, reviewing papers, and writing the publication.
The authors searched four databases in April 2023 for studies that:
- Included participants with a mean age between 10- 24 years
- Were a controlled trial of a worry/rumination/repetitive negative thinking intervention comparing to any form of control condition, including internet-delivered and face-to-face formats
- Used validated psychometric measures of worry/rumination/repetitive negative thinking and anxiety, depression, suicide, self-harm or psychosis
- Were published in a peer-reviewed journal in English or German.
Studies were excluded if the interventions were too general or were not a targeted treatment for worry/rumination/repetitive thinking, and if the trial was still ongoing.
One researcher screened all articles, with a random 30% of articles double-screened. Twelve articles were also included in the review based on the reference list of a previous systematic review (Bell et al., 2023).
Risk of bias was assessed using the Cochrane Risk of Bias Tool V.2 (Sterne et al., 2019), with most articles rated as having some concerns regarding risk of bias.
For the meta-analysis, a random effects model was used to pool effect sizes (Hunter-Schmidt g) of between-group effects for worry, rumination, repetitive negative thinking, anxiety and depression outcomes. A Robust Bayesian meta-analysis was also run (RoBMA g) to support the random effects model, which better accounts for publication bias.
Results
Sixteen articles were included in the review. Most studies were conducted in the UK and Europe (38%). Participants were mainly female (79%) and were primarily young adults (81%). Twenty interventions were included in the studies, and the most common (25%) was Rumination Focused Cognitive Behaviour Therapy (RFCBT). Other interventions included:
- Repetitive negative thinking-specific CBT
- Meta-cognitive therapy
- Working memory training
- Repetitive negative thinking-specific Acceptance and Commitment Therapy.
Effects on worry, rumination and repetitive negative thinking
There was strong evidence, and a small to moderate effect for the efficacy of repetitive negative thinking interventions (g(Hunter-Schmidt) = −0.51; g(RoBMA) = −0.50) and CBT (g(Hunter-Schmidt) = −0.42 to −0.44; g(RoBMA) = −0.34 to −0.41) respectively on reducing repetitive negative thinking.
Therapist-led interventions produced a larger effect than self-help strategies. The authors noted that there was also strong evidence indicating that some therapist-led interventions might be more effective than others but could not state which types due to a lack of evidence and heterogeneity between the included therapist-led interventions.
Effects on anxiety
Strong support was found for the efficacy of specific repetitive negative thinking interventions on anxiety. It was suggested that meta-cognitive therapy had a particularly strong impact on reducing repetitive negative thinking (g(Hunter-Schmidt) = −1.34; g(RoBMA) = -0.42). However, the authors noted that one study was skewing the results, so further exploration is needed. Therapist-led interventions also produced a larger effect than self-help strategies.
Effects on depression
There was a medium to strong effect overall for the repetitive negative thinking interventions on depression. There was stronger evidence for an effect of CBT on depression (g(Hunter-Schmidt) = −0.43; g(RoBMA) = −0.41). Again, therapist-led interventions produced a larger effect than self-help strategies. However, longer interventions (e.g., more than 2 hours in total) were also found to be more effective than medium and short interventions. There were not enough studies to determine any differences between the intervention types.
This meta-analysis found strong support for the effectiveness of repetitive negative thinking interventions on anxiety, depression and repetitive negative thinking, indicating its potential use as a transdiagnostic target.
Conclusions
The authors concluded that the evidence suggests that interventions specifically targeting negative thinking are effective in reducing anxiety and depression in young people. Longer interventions as opposed to interventions that were less than 2 hours in total, are suggested as being most beneficial. While the findings suggest that therapist-led interventions produced a larger effect than self-help strategies, more research is needed to further explore this.
Based on the findings, the young people with lived experience who co-produced the review emphasised that the interventions targeting repetitive negative thinking seem to be beneficial. It was noted, however, that cultural context should be considered, as they said it is likely that different interventions might be suited to people in some countries more than others.
Evidence suggests that therapist-led interventions targeting repetitive negative thinking are more effective than self-help strategies for anxiety and depression in young people, but more research is needed.
Strengths and limitations
A great strength of this research is that it was co-produced with young people with lived experience, and that the young people were a) from a range of countries, and b) involved in all stages of the research. This is important because young people have a right to participate in decisions which might affect them (Lundy, 2007).
This research built on a previous review (Bell et al., 2023) by expanding some key elements, such as lowering the age range of interest, including self-harm, suicide and psychosis as well as anxiety and depression, and including young people who would not meet clinical levels of symptoms. This places an important emphasis on early intervention and prevention work, which are important in helping to ensure better outcomes, and building skills that support good future mental health and wellbeing (McCorry & Mei, 2018).
Pre-registration of the study protocol with PROSPERO, and adherence to PRISMA guidelines and Cochrane Risk-of-Bias Tool, indicate that the study was conducted and reported in line with best practice, increasing the transparency and rigour of the research.
There was also no limitation on publication date, leading to a thorough review of existing literature and a reduced risk of publication-date bias. However, the exclusion of grey literature, dissertations, and unpublished studies will have reduced the pool of available research and could increase the likelihood of publication bias. Yet, unpublished research usually comprises a small proportion of reviews, and often will have little impact on the findings (Hartling et al., 2017).
The authors acknowledge some limitations in the evidence in this review, including:
- The low number of studies meeting the inclusion criteria, meaning the causal mechanisms underlying the efficacy of the interventions could not be examined as planned.
- Most studies focusing on anxiety and depression, with limited research available research on self-harm, suicide and psychosis, which were in the scope of the review.
- Limitations to the generalisability of the findings, given the population of the included studies was mainly university aged, and there was an over-representation of study populations from the Global North. As around 90% of young people globally live in the Global South (UNICEF, 2025), this means that there is a substantial amount of knowledge missing regarding the effectiveness of these interventions for young people.
While these are limitations of the research and evidence, they are not limitations of the methodology of this specific review, which was generally sound. However, the authors noted that they excluded CBT interventions that included components focused on repetitive negative thinking, which may mean that some evidence was missed in this review.
This is a strong systematic review and meta-analysis, co-produced with young people with relevant lived experience who were from four countries, and involved in all stages of the research
Implications for practice
The findings of this review reinforce the importance of early intervention and prevention work for young people’s mental health, as well as the importance of focusing on transdiagnostic factors such as repetitive negative thinking. If supported by prospective evidence that can investigate the causal mechanisms underlying the efficacy of the interventions, improving repetitive negative thinking has the potential to improve outcomes for young people experiencing a range of mental health difficulties. This may have a wide-reaching impact on young people’s mental health itself which, if taking a prevention and early intervention stance, would reduce the burden on specialist services later down the line.
There has been a recent call for integrated models of care that focus on transdiagnostic symptoms and factors to support young people’s mental health (Colizzi et al., 2020). Such transdiagnostic interventions that cut across traditional diagnostic boundaries of support may ease some of the growing burden on statutory services. By further exploring and then targeting underlying processes and symptoms that encompass several mental health difficulties, the onus on ‘treating’ one diagnosis at a time would be lifted. Afterall, transdiagnostic approaches reflect “the complexity, dimensionality and comorbidity that is the norm in clinical practice” (Dalgleish et al., 2020, p.179).
It’s worth noting that smaller effect sizes, as shown in this research, are expected in the context of prevention and early intervention with non-clinical samples. This is because less change is usually observed in these samples, when young people have fewer reported, or less severe difficulties, compared to clinical samples. The authors of this study suggest a range of research gaps and areas for future focus, including evidence from countries in the Global South, a wider range of psychological outcomes, and a focus on which repetitive negative thinking-specific interventions are most effective for whom. This might be in the form of longitudinal mixed methods studies, particularly in prevention and early intervention settings, and will be crucial for this developing area of focus, to best support young people.
Transdiagnostic interventions that cut across traditional diagnostic boundaries of support may ease some of the growing burden on statutory services, which in turn may increase prompt access to mental healthcare.
Statement of interests
None.
Links
Primary paper
Egan, S. J., Greene, D., Callaghan, T., Raghav, S., Funk, J., Badenbach, T., … & Kopf-Beck, J. (2025). Worry and rumination as a transdiagnostic target in young people: a co-produced systematic review and meta-analysis. Cognitive Behaviour Therapy, 54(1), 17-40.
Other references
Bell, I. H., Marx, W., Nguyen, K., Grace, S., Gleeson, J., & Alvarez-Jimenez, M. (2023). The effect of psychological treatment on repetitive negative thinking in youth depression and anxiety: A meta-analysis and meta-regression. Psychological Medicine, 53(1), 6-16.
Borkovec, T. D., Robinson, E., Pruzinsky, T., & DePree, J. A. (1983). Preliminary exploration of worry: Some characteristics and processes. Behaviour research and therapy, 21(1), 9-16.
Colizzi, M., Lasalvia, A., & Ruggeri, M. (2020). Prevention and early intervention in youth mental health: is it time for a multidisciplinary and trans-diagnostic model for care?. International Journal of Mental Health Systems, 14, 1-14.
Dalgleish, T., Black, M., Johnston, D., & Bevan, A. (2020). Transdiagnostic approaches to mental health problems: Current status and future directions. Journal of Consulting and Clinical Psychology, 88(3), 179.
Hartling, L., Featherstone, R., Nuspl, M., Shave, K., Dryden, D. M., & Vandermeer, B. (2017). Grey literature in systematic reviews: a cross-sectional study of the contribution of non-English reports, unpublished studies and dissertations to the results of meta-analyses in child-relevant reviews. BMC Medical Research Methodology, 17, 1-11.
Lundy, L. (2007). ‘Voice’ is not enough: conceptualising Article 12 of the United Nations Convention on the Rights of the Child. British Educational Research Journal, 33(6), 927-942.
McEvoy, P. M., Watson, H., Watkins, E. R., & Nathan, P. (2013). The relationship between worry, rumination, and comorbidity: Evidence for repetitive negative thinking as a transdiagnostic construct. Journal of Affective Disorders, 151(1), 313-320.
Moulds, M. (2017). Targeting unhelpful repetitive negative thinking in young people to prevent anxiety and depression. The Mental Elf.
Sterne, J. A., Savović, J., Page, M. J., Elbers, R. G., Blencowe, N. S., Boutron, I., … & Higgins, J. P. (2019). RoB 2: a revised tool for assessing risk of bias in randomised trials. bmj, 366.
UNICEF. Adolescent demographics. [Online]. Available https://data.unicef.org/topic/adolescents/overview/, Accessed 28 Jan 2025.
Watkins, E. R. (2008). Constructive and unconstructive repetitive thought. Psychological Bulletin, 134(2), 163.
Watkins, E. R., & Roberts, H. (2020). Reflecting on rumination: Consequences, causes, mechanisms and treatment of rumination. Behaviour Research and Therapy, 127, 103573.
Zagaria, A., Ballesio, A., Vacca, M., & Lombardo, C. (2023). Repetitive negative thinking as a central node between psychopathological domains: A network analysis. International Journal of Cognitive Therapy, 16(2), 143-160.
