Acceptance and Commitment Therapy on Psychological Flexibility, Values, and Well-Being: A Single-Case Experimental Study

NCT07620483 | Completed DMC

• 3 other identifiers: Universidad del ValleUNIVALLE-ACT-2025Faculty of Psychology
• Study Type: interventional
• Target: 12
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this clinical trial is to evaluate the effects of a brief Acceptance and Commitment Therapy (ACT)-based group intervention on psychological flexibility, values-based functioning, and psychological well-being in university students aged 18 to 28 years presenting elevated levels of emotional distress and psychological risk indicators. The main questions it aims to answer are: Does a brief ACT-based intervention reduce experiential avoidance and cognitive fusion in university students? Does the intervention improve present-moment awareness, values-based functioning, life satisfaction, and psychological flourishing? Participants will: Complete repeated self-report assessments across 13 measurement points distributed throughout baseline, intervention, and follow-up phases. Participate in five weekly ACT-based group intervention sessions delivered by trained clinical psychologists. Engage in experiential ACT exercises focused on acceptance, mindfulness, cognitive defusion, values clarification, and committed action. Complete between-session activities and behavioral practices related to the ACT processes addressed during the intervention. Participate in follow-up assessments to evaluate maintenance of treatment effects over time.

Conditions

Psychological Flexibility; Emotional Distress; Psychological Well-Being; Experiential Avoidance; Cognitive Fusion

Keywords

Acceptance and Commitment Therapy; Psychological Flexibility; Single-Case Experimental Design; Brief Psychological Intervention; Mental Health

Outcome Measures

Primary Outcomes (3)

• Mindful Attention Awareness Scale (MAAS)

  The Mindful Attention Awareness Scale (MAAS) is a 15-item self-report questionnaire designed to assess present-moment attention and awareness in daily life. Items are rated on a 6-point Likert-type scale ranging from 1 ("almost always") to 6 ("almost never"). Total scores are calculated by summing item responses, with higher scores indicating greater mindfulness and present-moment awareness.

  Weekly during baseline (4 weeks), intervention (6 weeks), and follow-up (3 weeks), up to 13 weeks

• Acceptance and Action Questionnaire-II (AAQ-II)

  The Acceptance and Action Questionnaire-II (AAQ-II) is a 7-item self-report questionnaire designed to assess experiential avoidance and psychological inflexibility. Items are rated on a 7-point Likert-type scale ranging from 1 ("never true") to 7 ("always true"). Total scores are calculated by summing item responses, with higher scores indicating greater experiential avoidance and psychological inflexibility.

  Weekly during baseline (4 weeks), intervention (6 weeks), and follow-up (3 weeks), up to 13 weeks.

• Cognitive Fusion Questionnaire (CFQ)

  The Cognitive Fusion Questionnaire (CFQ) is a 7-item self-report questionnaire designed to assess cognitive fusion. Items are rated on a 7-point Likert-type scale ranging from 1 ("never true") to 7 ("always true"). Total scores are calculated by summing item responses, with higher scores indicating greater cognitive fusion.

  Weekly during baseline (4 weeks), intervention (6 weeks), and follow-up (3 weeks), up to 13 weeks.

Secondary Outcomes (3)

• Valuing Questionnaire - Obstruction Subscale (VQ-Obstruction)

  Weekly during baseline (4 weeks), intervention (6 weeks), and follow-up (3 weeks), up to 13 weeks.

• Satisfaction With Life Scale (SWLS)

  Weekly during baseline (4 weeks), intervention (6 weeks), and follow-up (3 weeks), up to 13 weeks.

• Flourishing Scale (FS)

  Weekly during baseline (4 weeks), intervention (6 weeks), and follow-up (3 weeks), up to 13 weeks.

Study Arms (1)

ACT-Based Brief Group Intervention

EXPERIMENTAL

The intervention consisted of a brief ACT-based group protocol delivered weekly by trained clinical psychologists. The protocol targeted core ACT processes including acceptance, cognitive defusion, present-moment awareness, values clarification, and committed action. Sessions incorporated experiential exercises, metaphors, mindfulness practices, reflective activities, and between-session behavioral tasks designed to promote psychological flexibility and psychological well-being in university students.

Behavioral: Acceptance and Commitment Therapy (ACT)-Based Brief Group Intervention

Interventions

Acceptance and Commitment Therapy (ACT)-Based Brief Group Intervention BEHAVIORAL

The intervention consisted of a brief group-based Acceptance and Commitment Therapy (ACT) protocol designed to promote psychological flexibility and psychological well-being in university students presenting elevated emotional distress and psychological risk indicators. The protocol was grounded in the functional contextual approach and targeted core ACT processes, including acceptance, cognitive defusion, present-moment awareness, values clarification, and committed action. Participants were organized into small groups of 5 to 8 individuals and attended five weekly intervention sessions conducted by trained clinical psychologists with at least five years of clinical experience. Prior to implementation, therapists completed specialized ACT training delivered by an expert clinician with extensive experience in Acceptance and Commitment Therapy. The intervention protocol included an initial preliminary session focused on motivational engagement, informed consent procedures, feedback rega

Also known as: ACT Brief, ACT Protocol Group, ACT Intervention

ACT-Based Brief Group Intervention

Eligibility Criteria

• Age: 18 Years - 28 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• University students aged 18 years or older Interest in strengthening mental health and psychological well-being Voluntary agreement to participate in the study
• High-risk scores on at least one of the following screening instruments:
• Depression Anxiety Stress Scales (DASS-21) General Health Questionnaire (GHQ-12) State Worry Questionnaire-11 (SWQ-11)

You may not qualify if:

• Current psychological or psychiatric treatment Current use of psychiatric medication Diagnosis related to developmental or learning difficulties Failure to attend intervention sessions Incomplete participation in study assessments

Sponsors & Collaborators

• Universidad del Valle, Colombia: lead

Study Sites (1)

Faculty of Psychology, Universidad del Valle

Cali, Valle del Cauca Department, 760032, Colombia

Location

MeSH Terms

Conditions

Psychological Well-Being

Condition Hierarchy (Ancestors)

Personal Satisfaction; Behavior

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Masking Details: This was an open-label single-case experimental study. Participants, intervention providers, and investigators were aware of the intervention procedures, and no masking procedures were implemented.
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: The study employed a Single-Case Experimental Design (SCED) with repeated longitudinal measurements across three phases: baseline, intervention, and follow-up. Participants completed thirteen repeated assessments distributed across the study phases. The intervention consisted of five weekly ACT-based group sessions focused on psychological flexibility processes.

Study Record Dates

• First Submitted: May 12, 2026
• First Posted: June 2, 2026
• Study Start: April 1, 2025
• Primary Completion: June 15, 2025
• Study Completion: June 30, 2025
• Last Updated: June 2, 2026

Record last verified: 2026-05

Data Sharing

• IPD Sharing: Will not share

Locations

CO (1)