ACTsocially: The (Dis)Similarities of ACT for Changing Internalizing and Externalizing Symptomatology in Adolescence (ACTsocially)

Social functioning, fundamental to adolescent's development and mental health, may be impaired by polarizing problematic social functioning, namely externalizing symptoms manifested by Oppositional Defiant Disorder and internalizing symptoms portrayed by Social Anxiety Disorder. Despite their high prevalence and similar associated impairments, interventions targeting these disorders are differently conceived. Alternatively, Acceptance and Commitment Therapy (ACT) proposes that those apparently dissimilar social difficulties are rooted in similar processes. Though research has shown ACTs' efficacy in changing adults' internalizing and externalizing symptoms, studies on the potential of ACT in changing those problematics in adolescence are still scarce. This project proposes to conduct three clinical trials to test the efficacy and (dis)similarities of an transdiagnostic ACT intervention for changing internalizing and externalizing symptomatology in adolescents. It will amplify the transdiagnostic and evidence-based application of ACT to adolescents presenting polarizing disorders in the social functioning spectrum.

Study Overview

• Status: Recruiting
• Conditions: Oppositional Defiant Disorder; Social Anxiety Disorder (SAD)
• Intervention / Treatment: Behavioral: ACTsocially

Detailed Description

Adolescence represents vulnerability to mental health issues, with approximately 1 in 7 adolescents presenting mental disorders that, when untreated, lead to significant impairments and less long-term quality of life. Given that adolescents are hypersensitive to social stimuli and social exclusion, and place particular value in peer approval/influence, peer rejection in adolescence seems to increase the risk for developing mental disorders. Conversely, positive peer relationships may protect against mental health problems and promote resilience. This buffering effect may be absent in disorders related to adolescents' social functioning.

Oppositional Defiant Disorder (ODD) and Social Anxiety Disorder (SAD) are polarizing examples of problematic social functioning as adolescents with these diagnoses view the social world as a place of potential evaluation and rejection. ODD and SAD have alarming lifetime prevalence rates in adolescence, suggesting that these conditions are highly stable and predict later emotional and behavioral problems. Though their impact on socialization is similar (i.e., rejection, isolation), they have been differently conceptualized and intervened with (e.g., self-focused attention in SAD versus hostile attribution style in ODD).

Alternatively, Acceptance and Commitment Therapy (ACT) focuses on common underlying processes, rather than specific symptoms, as the foundation for social difficulties such as ODD or SAD. Specifically, Psychological Inflexibility (PI) - rigid attempts to control internal experiences and the inability to adapt one's behavior in the service of freely chosen values - is proposed as the basis of human suffering. PI stems from six interrelated processes: Cognitive Fusion, Experiential Avoidance, Attachment to the Conceptualized Self, Dominance of the Conceptualized Past/Feared Future, Lack of Values Clarity, and Inaction, Impulsivity or Avoidant Persistence. ACT aims to cultivate Psychological Flexibility (PF) - the ability to be in the present moment with willingness to be with the internal experience non-judgmentally and to act in a way that is congruent with ones' values. ACT relies on 6 core principles to cultivate PF, each opposing to one of the PI processes: Acceptance, Cognitive Defusion, Contact with Present Moment, Self-As-Context, Values, and Committed Action. Although there is evidence about PI processes as transdiagnostic factors underlying psychopathology and about the efficacy of ACT on adults' mental health in comparison with control conditions, research targeting adolescent samples (though emerging) is lacking.

Research has supported the efficacy of ACT interventions in adults with externalizing behavior. However, only a few works used ACT to address externalizing behavior in adolescents, though results were promising. There is evidence supporting the efficacy of ACT in treating SAD, though, again, only a few studies addressed this issue and found promising outcomes with adolescents. None of these works considered change in the processes of PI/PF and its intercorrelation with change in symptomatology, nor ACT's potential to promote similar change in these polarizing examples of problematic social functioning.

To overcome these shortcomings, we propose to take an ACT approach to adolescent ODD and SAD in a sequence of three clinical trials: A pilot single-arm clinical study of ACT applied to ODD, a Randomized Controlled Clinical Trial of ACT applied to SAD, and an equivalence clinical trial of ACT applied to ODD and SAD. These studies will be conducted to explore the (dis)similarity in efficacy of ACT for ODD and SAD, considering symptomatology, PI/PF processes and mental health as outcomes.

The research team will adapt, implement, and investigate the efficacy of a face-to-face ACT Intervention to adolescents presenting ODD or SAD via: 1. Changes in primary (i.e., disruptive behavior and anxiety symptoms) and secondary (i.e., mental health and PI/PF processes) outcomes following intervention - significant improvements are expected at post-intervention (i.e., in the SAD diagnosed intervention group in comparison with a control group and in the ODD diagnosed intervention group); 2. Examining the stability of change over time (i.e., 3- and 6-months follow-up) - improvements are expected to be maintained; 3. Comparing the efficacy of ACT between both intervention groups - Similar effects are expected on outcome measures for both intervention groups; 4. Investigating mechanisms of change following intervention in both intervention groups - Change in PI/PF is expected to predict change in outcome variables in both intervention groups.

All procedures involved in this project (described elsewhere in this form) were approved by the Ethics Committee of the Faculty of Psychology and Educational Sciences, University of Coimbra and the General Directorate of Education authorized the data collection protocol to be implemented in school contexts. Informed consent from adolescents and their parents/legal guardians will be required for all potential participants prior to any data collection. Adolescents and their parents/legal guardians will be informed that participation is voluntary and that they can decline to participate at any time during the project without any negative consequence. Moreover, they will be informed that the confidentiality of responses will be assured in all moments.

• Study Type: Interventional
• Enrollment (Estimated): 54
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Francisca Alves M.Sc.; Phone Number: +351 914309297; Email: mfrancisca.mca@gmail.com

Study Locations

• Portugal
  • Coimbra, Portugal
    • Recruiting
    • FPCEUC
    • Contact: FPCEUC; Phone Number: +351 239 851 450; Email: dir@fpce.uc.pt

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

Study I:

• Main diagnosis of Oppositional Defiant Disorder (ODD)
• Meeting diagnostic criteria for Social Anxiety Disorder (SAD)

Study II:

• Main diagnosis of Social Anxiety Disorder (SAD)
• Meeting diagnostic criteria for Oppositional Defiant Disorder (ODD)

Exclusion Criteria (applies to both studies):

• Impaired cognitive development based on school records
• Presence of psychotic symptoms according to the diagnostic interview
• Diagnosis of autism spectrum disorder according to the diagnostic interview
• Currently undergoing another psychological intervention for a psychiatric condition

Note: Comorbid conditions other than the co-occurrence of ODD and SAD will not be considered exclusion criteria.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Intervention Group (study I); Adolescents meeting diagnostic criteria for Oppositional Defiant Disorder. Participants receive the ACTsocially intervention. Assessments are conducted at pre-intervention and post-intervention (11 weeks later), and at 3 and 6-month follow-up.	Behavioral: ACTsocially; Adapted from the ACT@TeenSAD intervention program developed within the TeenSAD research project (NCT04979676), the ACTsocially intervention program is a structured, manualized face-to-face transdiagnostic intervention grounded in the PF model of ACT. The intervention consists of 11 weekly 50-minute sessions. Core content is organized across four modules (1: The role of psychological (in)flexibility; 2: The foundation of psychological flexibility; 3: Psychological flexibility in action; 4: Revision of gains and relapse prevention). Sessions follow a consistent structure beginning with a mindfulness exercise, followed by a brief review of the previous session and discussion of the adolescent's experiences with the between-session commitment. The therapist then introduces one or more activities centered on the weekly theme, which may involve psychoeducation, metaphors, or experiential exercises. Each session concludes with the introduction of a new commitment for the following week.
No Intervention: Control Group (study II); Adolescents meeting diagnostic criteria for Social Anxiety Disorder. Participants do not receive the ACTsocially intervention. Assessments are conducted at baseline, post-assessment (11 weeks later), and at 3 and 6-month follow-up.
Experimental: Intervention Group (study II); Adolescents meeting diagnostic criteria for Social Anxiety Disorder. Participants receive the ACTsocially intervention. Assessments are conducted at pre-intervention, post-intervention (11 weeks later), and at 3 and 6-month follow-up.	Behavioral: ACTsocially; Adapted from the ACT@TeenSAD intervention program developed within the TeenSAD research project (NCT04979676), the ACTsocially intervention program is a structured, manualized face-to-face transdiagnostic intervention grounded in the PF model of ACT. The intervention consists of 11 weekly 50-minute sessions. Core content is organized across four modules (1: The role of psychological (in)flexibility; 2: The foundation of psychological flexibility; 3: Psychological flexibility in action; 4: Revision of gains and relapse prevention). Sessions follow a consistent structure beginning with a mindfulness exercise, followed by a brief review of the previous session and discussion of the adolescent's experiences with the between-session commitment. The therapist then introduces one or more activities centered on the weekly theme, which may involve psychoeducation, metaphors, or experiential exercises. Each session concludes with the introduction of a new commitment for the following week.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Core Social Fears	The CSFS-A is a self-report questionnaire designed to assess adolescents' experiences of anxiety and behavioral avoidance across a range of commonly encountered social situations. Originally comprising 34 items answered twice - once for anxiety intensity and once for avoidance frequency - items are rated on a five-point Likert scale (1 = none / never, 5 = very much / almost always) for each dimension. In the refined measurement model, this scale is conceptualized in terms of three core social fear dimensions (i.e. Interaction, Performance, and Observation) and a general avoidance factor. Each of the resulting subscales (Observation, Performance, Interaction) and the General Avoidance factor yields a composite score reflecting the intensity of social fears or the degree of avoidance behavior. Internal consistency values for these scales were demonstrated to be acceptable to good across community and clinical adolescent samples.	Baseline, Week 11, Follow-Up 3 Months and Follow-Up 6 Months
Change in Disruptive Behavior	The DBDRS is a 45-item hetero-report scale for the assessment of DSM-V symptoms of attention deficit hyperactivity disorder (ADHD), oppositional defiant disorder (ODD) and conduct disorder (CD). Items (e.g., "Argues with adults") are rated using a four-point Likert-type scale (0 = "not at all" to 3 = "very much"). The DBDRS is organized into four subscales - inattention, hyperactivity/impulsivity, oppositional defiant disorder, and conduct disorder. For the current work, only the ODD scale will be used in the intervention group of Study I, both in its original version for caregivers' (i.e., parents/teachers) report and in a version designed within this work for adolescents' self-report. The original version achieved an excellent level of internal consistency (α = 0.93 for the ODD scale). Invariance testing also suggested that the scale's internal structure is similar across key demographics such as age and sex.	Baseline, Week 11, Follow-Up 3 Months and Follow-Up 6 Months
Change in Aggressive Behaviors	The RPEQ is a 14-item self-report scale that assesses aggression, victimization and prosocial behavior. Each item is presented in two versions, one for practicing a given behavior and another for receiving that behavior. For the current work only the practice of aggression measures will be used within the intervention group of Study I. Items are rated on 5-point Likert scale (ranging from 1 = "never" to 5 = "a few times a week") and are organized into overt aggression, relational aggression, and reputational aggression. Factors achieved at least acceptable internal consistency values with Cronbach's alpha values of .88 for overt aggression, .75 for relational aggression, and .91 for reputational aggression. Evidence was also found in favor of the construct validity of these measures.	Baseline, Week 11, Follow-Up 3 Months and Follow-Up 6 Months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Psychological Flexibility	The MPFI-24A is a 24-item self-report scale for the assessment of psychological flexibility (PF) and inflexibility (PI) that will be used to assess all groups considered in this research. The scale comprises 12 subscales, representing the six PF processes and the six PI processes. Items (e.g., "I opened myself to all of my feelings, the good and the bad") are answered on a 6-point Likert scale (ranging from 1 = 'never true' to 6 = 'always true') regarding how true the item was for the respondent in the previous 2 weeks. In the adolescent version, the composite indices (PF and PI) showed excellent internal consistency (α = .90 and α = .85, respectively) and the 12 factors revealed acceptable reliability with values that varied between .61 and .83.	Baseline, Week 11, Follow-Up 3 Months and Follow-Up 6 Months
Change in Mental Health	The MHC-SF is a 14-item self-report scale for the assessment of adolescents' mental health estimated from the perceived degree of emotional, social and psychological well-being; it will be used to assess all groups considered in this research. Items are answered on a 5-point Likert scale (ranging from 0 = "never" to 5 = "every day") regarding the number of times during the previous month the respondent felt a certain way. The used Portuguese version achieved at least good levels of internal consistency (α = 0.90 on the global scale and between 0.80 and 0.85 on the subscales.	Baseline, Week 11, Follow-Up 3 Months and Follow-Up 6 Months

Collaborators and Investigators

• Sponsor: University of Coimbra
• Collaborators: Foundation for Science and Technology, Portugal

Publications and helpful links

General Publications

• 28. Matos, A. P., André, R. S., Cherpe, S., Rodrigues, D., Figueira, C., & Pinto, A. M. (2010). Estudo Psicométrico preliminar da Mental Health Continuum - Short Form - for youth numa amostra de adolescentes portugueses. Psychologica, 53, 131-156. https://doi.org/10.14195/1647-8606_53_7
• 27. Rolffs, J. L., Rogge, R. D., & Wilson, K. G. (2018). Disentangling Components of Flexibility via the Hexaflex Model: Development and Validation of the Multidimensional Psychological Flexibility Inventory (MPFI). Assessment, 25(4), 458-482. https://doi.org/10.1177/1073191116645905
• 26. Queirós, A. N., & Vagos, P. (2016). Measures of aggression and victimization in portuguese adolescents: Cross-cultural validation of the Revised Peer Experience Questionnaire. Psychological Assessment, 28(10), e141-e151. https://doi.org/10.1037/pas0000363
• 25. Fosco, W. D., Babinski, D. E., & Waschbusch, D. A. (2023). The disruptive behavior disorders rating scale: Updated factor structure, measurement invariance, and national caregiver norms. Journal of Pediatric Psychology, 48(5), 468-478. https://doi.org/10.1093/jpepsy/jsad006
• 24. Vagos, P., Figueiredo, D.V. & Cunha, M. The Core Social Fears Scale for Adolescents: Psychometric appraisal based on community and clinical samples. Eur Child Adolesc Psychiatry (2025). https://doi.org/10.1007/s00787-025-02824-4
• 23. Alves, F., Figueiredo, D. V., & Vagos, P. (2022). Acceptance and Commitment Therapy for Social Anxiety Disorder in Adolescence: Preliminary Appraisal Based on a Case Study Approach. Clinical Case Studies, 0(0). https://doi.org/10.1177/15346501221144069
• 22. Azadeh, S. M., Kazemi-Zahrani, H., & Besharat, M. A. (2015). Effectiveness of Acceptance and Commitment Therapy on Interpersonal Problems and Psychological Flexibility in Female High School Students With Social Anxiety Disorder. Global Journal of Health Science, 8(3), 131-138. https://doi.org/10.5539/gjhs.v8n3p131
• 21. Caletti, E., Massimo, C., Magliocca, S., Moltrasio, C., Brambilla, P., & Delvecchio, G. (2022). The role of the acceptance and commitment therapy in the treatment of social anxiety: An updated scoping review. Journal of Affective Disorders, 310, 174-182. https://doi.org/10.1016/j.jad.2022.05.008
• 20. Livheim, F., Tengström, A., Andersson, G., Dahl, J., Björck, C., & Rosendahl, I. (2020). A quasi-experimental, multicenter study of acceptance and commitment therapy for antisocial youth in residential care. Journal of Contextual Behavioral Science, 16, 119-127. https://doi.org/10.1016/j.jcbs.2020.03.008
• 19. Theodore-Oklota, C., Orsillo, S. M., Lee, J. K., & Vernig, P. M. (2014). A pilot of an acceptance-based risk reduction program for relational aggression for adolescents. Journal of Contextual Behavioral Science, 3, 109-116. https://doi.org/10.1016/j.jcbs.2014.03.001
• 18. Berkout, O. V., Tinsley, D., & Flynn, M. K. (2019). A review of anger, hostility, and aggression from an ACT perspective. Journal of Contextual Behavioral Science, 11, 34-43. https://doi.org/10.1016/j.jcbs.2018.12.001
• 17. Moreno, P. M., & Blasco, R. Q. (2019). Una revisión de la aplicación de la Terapia de Aceptación y Compromiso con niños y adolescentes. [Acceptance and commitment therapy with children and adolescents: A review.]. International Journal of Psychology & Psychological Therapy, 19, 173-188.
• 16. Powers, M. B., Vörding, M. B. Z. V. S., & Emmelkamp, P. M. G. (2009). Acceptance and Commitment Therapy: A Meta-Analytic Review. Psychotherapy and Psychosomatics, 78(2), 73-80. https://doi.org/10.1159/000190790
• 15. A-Tjak, J. G. L., Davis, M. L., Morina, N., Powers, M. B., Smits, J. A. J., & Emmelkamp, P. M. G. (2015). A Meta-Analysis of the Efficacy of Acceptance and Commitment Therapy for Clinically Relevant Mental and Physical Health Problems. Psychotherapy and Psychosomatics, 84(1), 30-36. https://doi.org/10.1159/000365764
• 14. Dimidjian, S., Arch, J. J., Schneider, R. L., Desormeau, P., Felder, J. N., & Segal, Z. V. (2016). Considering Meta-Analysis, Meaning, and Metaphor: A Systematic Review and Critical Examination of 'Third Wave' Cognitive and Behavioral Therapies. Behavior Therapy, 47(6), 886-905. https://doi.org/10.1016/j.beth.2016.07.002
• 13. Gloster, A. T., Walder, N., Levin, M. E., Twohig, M. P., & Karekla, M. (2020). The empirical status of acceptance and commitment therapy: A review of meta-analyses. Journal of Contextual Behavioral Science, 18, 181-192. https://doi.org/10.1016/j.jcbs.2020.09.009
• 12. Hayes, S. C., Pistorello, J., & Levin, M. E. (2012). Acceptance and Commitment Therapy as a Unified Model of Behavior Change. The Counseling Psychologist, 40(7), 976-1002. https://doi.org/10.1177/0011000012460836
• 11. Hayes, S. C., Luoma, J. B., Bond, F. W., Masuda, A., & Lillis, J. (2006). Acceptance and commitment therapy: Model, processes and outcomes. Behaviour Research and Therapy, 44(1), 1-25. https://doi.org/10.1016/j.brat.2005.06.006
• 10. Hayes, S. C., Strosahl, K. D., & Wilson, K. G. (1999). Acceptance and commitment therapy: An experiential approach to behavior change. Guilford Press.
• 9. Hiemstra, W., De Castro, B. O., & Thomaes, S. (2019). Reducing Aggressive Children's Hostile Attributions: A Cognitive Bias Modification Procedure. Cognitive Therapy and Research, 43(2), 387-398. https://doi.org/10.1007/s10608-018-9958-x
• 8. Leigh, E., & Clark, D. M. (2018). Understanding Social Anxiety Disorder in Adolescents and Improving Treatment Outcomes: Applying the Cognitive Model of Clark and Wells (1995). Clinical Child and Family Psychology Review, 21(3), 388-414. https://doi.org/10.1007/s10567-018-0258-5
• 7. Merikangas, K. R., He, J.-P., Burstein, M., Swanson, S. A., Avenevoli, S., Cui, L., Benjet, C., Georgiades, K., & Swendsen, J. (2010). Lifetime prevalence of mental disorders in U.S. adolescents: Results from the National Comorbidity Survey Replication--Adolescent Supplement (NCS-A). Journal of the American Academy of Child and Adolescent Psychiatry, 49(10), 980-989. https://doi.org/10.1016/j.jaac.2010.05.017
• 6. van Harmelen, A.-L., Kievit, R. A., Ioannidis, K., Neufeld, S., Jones, P. B., Bullmore, E., Dolan, R., Fonagy, P., & Goodyer, I. (2017). Adolescent friendships predict later resilient functioning across psychosocial domains in a healthy community cohort. Psychological Medicine, 47(13), 2312-2322. https://doi.org/10.1017/S0033291717000836
• 5. Arseneault, L. (2018). Annual Research Review: The persistent and pervasive impact of being bullied in childhood and adolescence: implications for policy and practice. Journal of Child Psychology and Psychiatry, and Allied Disciplines, 59(4), 405-421. https://doi.org/10.1111/jcpp.12841
• 4. Orben, A., Tomova, L., & Blakemore, S.-J. (2020). The effects of social deprivation on adolescent development and mental health. The Lancet. Child & Adolescent Health, 4(8), 634. https://doi.org/10.1016/S2352-4642(20)30186-3
• 3. Blakemore, S.-J., & Mills, K. L. (2014). Is adolescence a sensitive period for sociocultural processing? Annual Review of Psychology, 65, 187-207. https://doi.org/10.1146/annurev-psych-010213-115202
• 2. UNICEF (Ed.). (2021). On my mind: Promoting, protecting and caring for children's mental health. UNICEF.
• 1. Mental health of adolescents. (n.d.). Retrieved 20 February 2023, from https://www.who.int/news-room/fact-sheets/detail/adolescent-mental-health

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2023
• Primary Completion (Estimated): September 30, 2027
• Study Completion (Estimated): September 30, 2027

Study Registration Dates

• First Submitted: March 2, 2026
• First Submitted That Met QC Criteria: March 2, 2026
• First Posted (Actual): March 6, 2026

Study Record Updates

• Last Update Posted (Actual): March 10, 2026
• Last Update Submitted That Met QC Criteria: March 6, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Adolescents; Acceptance and Commitment Therapy; Social Anxiety Disorder; Psychological Flexibility; Oppositional Defiant Disorder; Psychological Inflexibility
• Additional Relevant MeSH Terms: Mental Disorders; Neurodevelopmental Disorders; Attention Deficit and Disruptive Behavior Disorders; Phobic Disorders; Anxiety Disorders; Phobia, Social; Oppositional Defiant Disorder
• Other Study ID Numbers: 2023.03831.BD

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No