Group-based ACT for Psychological Distress of Young People

Background and Rationale Mental health problems among adolescents and young adultsrepresent a significant and increasing public health concern. A substantial proportion ofyoung people experience symptoms of depression, anxiety, and related psychologicaldistress during a developmental period characterized by major psychological, social, andbiological transitions. These challenges may interfere with identity development,educational attainment, and social functioning, with potential long‐term consequences forhealth and well‐being .At the same time, mental health services face increasing demand and limited capacity,resulting in prolonged waiting times and restricted access to timely care. Traditionaloutpatient treatment is primarily delivered as individual psychotherapy, which limits thenumber of patients that can be treated. There is therefore a need to evaluate alternativeand potentially more scalable treatment formats that can maintain or improve clinicaloutcomes while increasing accessibility.Acceptance and Commitment Therapy (ACT) is a transdiagnostic behavioral intervention thataims to improve psychological functioning by enhancing psychological flexibility. Theability to act in accordance with personal values while remaining in contact withdifficult internal experiences. Rather than focusing solely on symptom reduction, ACTtargets core processes such as acceptance, cognitive defusion, present‐moment awareness,values clarification, and committed action.Although ACT has a substantial evidence base in adult populations, research on itseffectiveness for young people remains more limited, particularly in routine clinicalsettings and in comparison with standard care. Group‐based formats may represent anefficient way of delivering ACT, while also offering therapeutic benefits such as peersupport, normalization, and shared learning. The present study addresses important gapsin the literature by evaluating a structured group‐based ACT intervention tailored foryoung people, compared with treatment as usual (TAU), within specialized mental healthservices.Study Objectives The primary objective of the study is to evaluate the effectiveness ofgroup‐based ACT compared with treatment as usual in reducing symptoms of depression andanxiety among young people aged 16‐25.Secondary objectives include: ‐ Evaluating the impact of the intervention on psychological well‐being, quality oflife, and functional outcomes ‐ Assessing whether group‐based ACT leads to comparable or improved remission ratesrelative to TAU ‐ Investigating mechanisms of change, particularly the role of psychologicalflexibility related to the ACT processes ‐ Exploring potential moderators of treatment outcome, including demographic andclinical characteristicsStudy DesignThis study is a randomized controlled trial (RCT) with two parallel treatment arms: 1. Group‐based Acceptance and Commitment Therapy (ACT) 2. Treatment as usual (TAU), typically consisting of individual psychotherapyParticipants meeting eligibility criteria will be randomly allocated to one of thetwo conditions. The study is conducted in routine clinical settings acrosschild/adolescent (BUP) and adult (DPS) mental health services, as well as incollaboration with primary care services, to enhance ecological validity andgeneralizability .The target sample size is 212 participants, accounting for expected attrition andensuring adequate statistical power for both outcome and process analyses .ParticipantsInclusion criteria:Age 16‐25 years Moderate symptoms of depression, score of 14 and above in the DASS 21questionnaireExclusion criteria:Severe psychiatric conditions requiring alternative treatment (e.g., psychosis, bipolardisorder) Active substance dependence Acute suicidal ideation or behavior Eatingdisorders or developmental disorders requiring specialized interventions Participantswith specific disorders for which established evidence‐based treatments are indicated(e.g., OCD) will be offered those treatments outside the study.Interventions:Group‐based ACTThe experimental intervention is a structured group program based on Acceptance andCommitment Therapy, adapted for young people using the DNA‐V framework. The interventionfocuses on developing skills in: ‐ Awareness of internal experiences ‐ Acceptance and willingness ‐ Cognitive defusion ‐ Values clarification ‐ Committed action The group format aims to promote experiential learning and peerinteraction. The intervention consists of multiple sessions delivered over a definedtreatment period, with each group including up to 10 participants and led by trainedtherapists. Sessions are manualized to ensure consistency and fidelity, andadherence will be monitored through supervision and video recordings .Treatment as Usual (TAU) Participants allocated to TAU will receive standard care withinmental health services. This typically involves individual psychotherapy delivered by aclinician. The content, frequency, and duration of treatment are determined by clinicalneeds and routine practice, reflecting real‐world conditions.Procedures and Assessments:Participants will undergo a baseline assessment prior to randomization, includingdiagnostic evaluation using structured clinical interviews. Follow‐up assessments will beconducted at multiple time points: ‐ Baseline (pre‐treatment) ‐ During treatment (6 weeks) ‐ Post‐treatment (12 weeks) ‐ 6‐month follow‐up ‐ 12‐month follow‐upOutcome data will be collected using a combination of clinician‐administered interviewsand validated self‐report measures assessing: ‐ Depression and anxiety symptoms ‐ General psychological distress ‐ Quality of life ‐ Functional impairment ‐ Psychological processes relevant to ACT (e.g., flexibility, mindfulness,values‐based action) In addition to these scheduled assessments, ecologicalmomentary assessment (EMA) will be conducted using a digital platform. Participantswill complete brief daily measures during the treatment period and periodicfollow‐up assessments thereafter. This approach allows for detailed analysis oftemporal changes and treatment processes in real‐world contexts .OutcomesPrimary outcomes:• Changes in symptoms of depression and anxietySecondary outcomes: ‐ Psychological well‐being ‐ Quality of life ‐ Functional impairment ‐ Remission ratesProcess outcomes: ‐ Psychological flexibility ‐ Emotional regulation ‐ Mindfulness ‐ Self‐compassion ‐ Values‐consistent behaviorStatistical Analysis Data will be analyzed using appropriate statistical methods forlongitudinal and randomized designs. Primary analyses will compare changes in outcomemeasures between treatment conditions over time.Secondary analyses will examine: ‐ Mediation effects to identify mechanisms of change ‐ Moderation effects to identify subgroups for whom the treatment is particularlyeffective Missing data will be handled using established statistical techniquesappropriate for repeated measures designs.Ethical Considerations Participation in the study is voluntary, and all participants willprovide informed consent prior to inclusion. Participants may withdraw at any timewithout consequences for their access to treatment.The interventions evaluated in this study are based on established therapeutic approachesand are not expected to pose significant risk. However, participation in group‐basedtreatment may be experienced as challenging for some individuals. Measures are in placeto monitor and address adverse reactions, including the presence of trained therapistsand access to follow‐up support .The study will be conducted in accordance with ethical guidelines and has been approvedby the regional ethics committee.Significance This study will contribute to the evidencebase for psychological treatmentsfor young people by evaluating a scalable, group‐based intervention within routineclinical practice. The findings may inform service development and improve access toeffective mental health care for this population. Additionally, the study will provideinsight into the mechanisms underlying therapeutic change, supporting further refinementof interventions based on ACT principles.