Efficacy of a Group-Based Acceptance and Commitment Therapy Protocol Compared to an Active Control in University Students With Emotional Symptoms: a Randomized Controlled Trial With an Ideographic Approach
Phase: NA
Conditions: Depression, Anxiety
Sponsor: Mónica Larrosa Signorelli

Official Title:​
Group-Based Acceptance and Commitment Therapy Versus Active Control in University 
Students With Emotional Symptoms 
NCT:​
CE2025/37 
Study Protocol  
Document date:​
27 March 2026 
 

1. Official Title 
Efficacy of a Group-Based Acceptance and Commitment Therapy Protocol Compared to an 
Active Control in University Students With Emotional Symptoms: a Randomized Controlled 
Trial With an Ideographic Approach. 
2. Scientific Background and Rationale 
Emotional disorders such as anxiety and depression are highly prevalent among university 
students, representing a major public health concern. These conditions frequently co-occur 
and share transdiagnostic processes, particularly repetitive negative thinking (RNT) and 
psychological inflexibility. 
Acceptance and Commitment Therapy (ACT) is a process-based intervention that targets 
these mechanisms by promoting psychological flexibility. Evidence supports its efficacy 
across emotional disorders and student populations, particularly in group formats. 
However, most clinical trials rely on retrospective self-report measures, which may fail to 
capture dynamic psychological change. Ecological Momentary Assessment (EMA) enables 
real-time, repeated measurement of symptoms and psychological processes, improving 
ecological validity and sensitivity to change. 
To date, no randomized controlled trial has integrated: 
➔​ Group-based ACT 
➔​ An active control condition (non-directive therapy) 
➔​ Daily and weekly EMA in a university population in Latin America. 
This study aims to address this gap and provide both clinical and methodological 
contributions. 
3. Objectives 
Primary Objective 
To evaluate whether a group-based ACT intervention is more effective than a non-directive 
supportive therapy (NDT) in reducing emotional symptoms (depression and anxiety). 
Secondary Objectives 
1.​ To assess changes in:​
​
- Psychological flexibility​
​
- Repetitive negative thinking​
​
- Meaning in life 
2.​ To examine trajectories of change using EMA (daily and weekly). 
3.​ To compare the sensitivity of EMA versus traditional pre–post measures. 

4.​ To explore participants’ subjective experience of change. 
4. Study Design 
➔​ Type: Randomized controlled trial 
➔​ Design: Parallel-group 
➔​ Allocation ratio: 1:1 
➔​ Blinding: Outcome assessors and data analysts blinded 
5. Methods 
5.1 Participants 
University students aged 18–28 years will be recruited from universities in Montevideo, 
Uruguay. 
Inclusion Criteria 
●​ PHQ-9 ≥ 8 and/or GAD-7 ≥ 8 
●​ Willingness to participate in group intervention and EMA assessment 
Exclusion Criteria 
➔​ Current suicide risk 
➔​ Psychotic disorders 
➔​ Substance abuse 
➔​ Clinical conditions requiring immediate specialized care 
5.2 Interventions 
Experimental Group (ACT) 
Participants will receive a manualized group-based ACT intervention: 
➔​ 5 weekly sessions 
➔​ 90 minutes per session 
➔​ Focus on: 
-​
Acceptance 
-​
Cognitive defusion 
-​
Values clarification 
-​
Committed action 
Control Group (NDT) 
Participants will receive a non-directive supportive group therapy: 

➔​ Same duration and format (5 weekly sessions - 90 minutes per session) 
➔​ Focus on: 
-​
Empathy 
-​
Emotional validation 
-​
Active listening 
➔​ No structured therapeutic techniques 
5.3 Outcomes 
Primary Outcomes 
➔​ Change in emotional symptoms measured by the Patient Health Questionnaire-4 
(PHQ-4) 
Secondary Outcomes 
➔​ Change in psychological flexibility and inflexibility measured by the Flexible and 
Inflexible Behavior Questionnaire (CCFI) 
➔​ Change in repetitive negative thinking measured by the Repetitive Negative Thinking 
Questionnaire-3 (RNT-3) 
➔​ Change in anxiety symptoms measured by the Generalized Anxiety Disorder-7 
(GAD-7 total score) 
➔​ Change in depressive symptoms measured by the Patient Health Questionnaire-9 
(PHQ-9 total score) 
➔​ Change in sense of purpose in life measured by the Purpose in Life Test (PIL-Test 
total score) 
➔​ Perceived change and intervention acceptability 
 
-​
Measures: 
EMA Measures 
➔​ Daily: PHQ-4, CCFI, RNT-3 
➔​ Weekly: PHQ-4, CCFI, RNT-3 
Pre-post-follow-up Measures: 
➔​ PHQ-9 
➔​ GARD-7 
➔​ PIL-Test 
Qualitative Outcomes 
➔​ Post-intervention semi-structured interviews 
5.4 Procedure 
➔​ Screening and baseline assessment (Week 1) 

➔​ Baseline EMA period (Weeks 2–5) 
➔​ Intervention phase (Weeks 6–10) 
➔​ Post-treatment assessment (Week 11) 
➔​ Follow-up assessments (Weeks 15 and 23) 
EMA data will be collected continuously throughout the study using a mobile application. 
5.5 Randomization 
Participants will be randomly assigned (1:1) to ACT or NDT using a computer-generated 
random sequence.  
6. Ethical Considerations and Amendments 
This study has been submitted for approval to an institutional Human Subjects Protection 
Review Board. 
All protocol amendments approved by the ethics committee prior to submission and 
applicable to all trial sites are incorporated into this protocol. 
Any future modifications to: 
➔​ study design 
➔​ eligibility criteria 
➔​ outcomes 
➔​ analyses 
will be: 
1.​ Approved by the ethics committee before implementation 
2.​ Documented with justification and date 
3.​ Updated in the trial registry when applicable 
Participant safety procedures include risk assessment for suicidality and referral protocols 
when necessary. 
7. Data Management 
All participant data will be de-identified and stored securely. Only the research team will 
have access to identifiable data. Data sharing will follow ethical and regulatory standards.