Brief-intensive CBT Versus Once-weekly CBT in Anxiety-related Disorders (KOMMA)

May 26, 2026 updated by: Adrie Seldenrijk, Amsterdam UMC, location VUmc

Fast Recovery From Anxiety-related Disorders: Brief-intensive CBT Versus Once-weekly CBT

The goal of this clinical trial is to compare brief-intensive cognitive-behaviour therapy (CBT) with regular weekly CBT in people with anxiety-related disorders.

The main question to answer is: will brief-intensive CBT improve functioning (work, family, social) more and faster than does regular weekly CBT?

Participants will be asked to follow CBT treatment (20 sessions of 45 minutes in both conditions), and participate in 7 measurements with a total duration of 5 hours over 1 year.

Researchers will compare:

  • Brief-intensive CBT: 16 sessions in 2 weeks + 4 follow-up sessions within 3 months
  • Regular CBT with 20 weekly sessions in 6 months

Study Overview

Detailed Description

Rationale: Anxiety-related disorders (i.e., obsessive compulsive, health anxiety and trauma disorders) affect about 10% of the adults. Though clinically heterogeneous, transdiagnostic aspects are expected disasters, anxiety and avoidance. Profound impairments include work and family functioning. Many enter a vicious circle with comorbidity and further decline in quality of life. Hence, the impact on functioning is tremendous, with anxiety-related disorders rating highest on disability rankings in the age 15-64 years. Cognitive behavioral therapy (CBT) is the preferred and often only psychotherapy for these disorders. Because guidelines are based on weekly sessions, recovery takes half a year at least. Based on initial research findings, we expect faster recovery by providing CBT in a brief-intensive format (BI-CBT), with clear benefts for patients, families and society. Some institutions already provide BI-CBT. However, evidence to justify this or to further implement BI-CBT is insufficient.

Study design: a parallel-group randomised controlled multicenter intervention study.

Study population: Adults aged 18-65 yr old with an anxiety-related disorder (panic, agrophobia, social anxiety, generalised anxiety obsessions/compulsions, health anxiety and post-traumatic stress)

Intervention (if applicable): One group receives BI-CBT (16 sessions in 2 weeks + 4 follow up sessions) and the other group receives 20 weekly CBT sessions. Treatment in both conditions can be personalised by a focus on work or family functioning.

Main study parameters/endpoints: The main study parameter is the 'area under the curve' for 6-month health and disability. Also, 1 year efficacy (both on functioning and symptom-level), cost-effectiveness, and feasibility will be assessed. Potential predictors of treatment preference, efficacy and drop-out will be explored.

All patients are expected to follow CBT (20 sessions of 45min) and participate in 7 measurements over 1 year.

The general measurements are online questionnaires and interviews by telephone, asking about someones functioning, quality of life and symptoms of anxiety or depression, how one copes with these and what one expects of the therapy.

The acronym KOMMA is based on the Dutch translation of 'to put a quick end to anxiety': Korte Metten Met Angst.

Study Type

Interventional

Enrollment (Estimated)

120

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

      • Amstelveen, Netherlands
        • GGZ inGeest, polikliniek Angst & Dwang, locatie Amstelmere
      • Amsterdam, Netherlands
        • GGZ inGeest, polikliniek Angst & Dwang, locatie De Nieuwe Valerius
      • Haarlem, Netherlands
        • GGZ inGeest, polikliniek Angst & Dwang, locatie Zuiderpoort
      • Hilversum, Netherlands
        • GGZ Centraal, Algemeen Specialistische Polikliniek
      • Hoofddorp, Netherlands
        • GGZ inGeest, polikliniek Angst & Dwang, locatie Spaarnepoort
      • Utrecht, Netherlands
        • Altrecht Academisch Angstcentrum

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

Age 18 years or older;

Reaching out for mental health care for one of the following disorders:

panic disorder, agoraphobia, generalised anxiety disorder, social anxiety disorder, posttraumatic stress disorder, obsessive-compulsive disorder, health anxiety disorder.

Exclusion Criteria:

  • Is in need of emergency mental health care
  • Has insufficient language skills in Dutch
  • Has evident cognitive limitations
  • Has had changes in the use of medication during the last 3 months.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Brief-Intensive CBT
16 sessions in 2 weeks + 4 follow up sessions. The CBT consists of 16 sessions exposure therapy, spread over 4 half-days in 2 weeks, + 4 sessions within 3 months.
The intervention is brief-intensive, guided exposure therapy and consists of 16 sessions exposure therapy, spread over 4 half-days in 2 weeks plus 4 follow-up sessions within 3 months.
Other Names:
  • exposure therapy
Active Comparator: weekly CBT
20 weekly CBT sessions within 5 to 6 months. The CBT consists of exposure therapy.
The intervention is brief-intensive, guided exposure therapy and consists of 16 sessions exposure therapy, spread over 4 half-days in 2 weeks plus 4 follow-up sessions within 3 months.
Other Names:
  • exposure therapy

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Area Under the health and disability Curve at 6 months
Time Frame: baseline, 2 weeks, 4 weeks, 2 months, 3 months, 6 months
The 'area under the curve' for health and disability is based on the 36-item self-report World Health Organisation Disability Assessment Schedule (WHODAS 2.0). The WHODAS 2.0 captures the level of functioning in six domains of life: Cognition, Mobility, Self-care, Getting along, Life activities, Participation. Possible total scores of the items across all domains range 0 - 100. Lower scores indicate less disability.
baseline, 2 weeks, 4 weeks, 2 months, 3 months, 6 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Area Under the health and disability Curve at 12 months
Time Frame: baseline, 2 weeks, 4 weeks, 2 months, 3 months, 6 months, 12 months
The 'area under the curve' for health and disability is based on the 36-item self-report World Health Organisation Disability Assessment Schedule (WHODAS 2.0). The WHODAS 2.0 captures the level of functioning in six domains of life: Cognition, Mobility, Self-care, Getting along, Life activities, Participation. Possible total scores of the items across all domains range 0 - 100. Lower scores indicate less disability.
baseline, 2 weeks, 4 weeks, 2 months, 3 months, 6 months, 12 months
Change from baseline in severity of anxiety symptoms at 3 months
Time Frame: baseline and 3 months
Severity of anxiety-related disorder, measured with the following disorder-specific severity questionnaires: the 24-item Liebowitz Social Anxiety Scale self-report version, the 7-item Panic Disorder Severity Scale self-report version, the 15-item Fear Questionnaire, the 16-item Penn State Worry Questionnaire, the 10-item Yale-Brown Obsessive Compulsive Scale self-report version, the 20-item PTSD checklist for the DSM-5, or the 14-item Whitely Index. Higher scores indicate higher symptom severity. Z-scores will be calculated from individual scores for group-level analyses.
baseline and 3 months
Change from baseline in severity of depressive symptoms at post-treatment
Time Frame: baseline and 3 or 6 months
Severity of depressive symptoms are measured with the 30-item Inventory for Depressive Symptomatology self-report questionnaire. Higher scores indicate higher symptom severity.
baseline and 3 or 6 months
Change from baseline in severity of depressive symptoms at 3 months
Time Frame: baseline and 3 months
Severity of depressive symptoms are measured with the 30-item Inventory for Depressive Symptomatology self-report questionnaire. Higher scores indicate higher symptom severity.
baseline and 3 months
Change from baseline in severity of depressive symptoms at 12 months
Time Frame: baseline and 12 months
Severity of depressive symptoms are measured with the 30-item Inventory for Depressive Symptomatology self-report questionnaire. Higher scores indicate higher symptom severity.
baseline and 12 months
Remission rates from anxiety-related disorder at post-treatment
Time Frame: 3 or 6 months
Remission of diagnoses of anxiety-related disorders is assessed using the Mini International Neuropsychiatric Interview - Simplified for DSM-5, Dutch version 1.1 (Overbeek & Schruers, 2019).
3 or 6 months
Remission rates from anxiety-related disorder at 12 months
Time Frame: 12 months
Remission of diagnoses of anxiety-related disorders is assessed using the Mini International Neuropsychiatric Interview - Simplified for DSM-5, Dutch version 1.1 (Overbeek & Schruers, 2019).
12 months
New-onset anxiety-related or depressive disorder post-treatment
Time Frame: baseline, 3 or 6 months
The new onset of anxiety-related or depressive disorder between baseline and post-treatment is assessed using the Mini International Neuropsychiatric Interview - Simplified for DSM-5, Dutch version 1.1 (Overbeek & Schruers, 2019)
baseline, 3 or 6 months
New-onset anxiety-related or depressive disorder at 12 months
Time Frame: 12 months
The new onset of anxiety-related or depressive disorder between baseline and post-treatment is assessed using the Mini International Neuropsychiatric Interview - Simplified for DSM-5, Dutch version 1.1 (Overbeek & Schruers, 2019)
12 months
Productivity costs over 12 months
Time Frame: 3months, 6months, 12 months
Productivity losses are assessed using the iMTA Productivity Cost Questionnaire (iPCQ). The iPCQ is a 12-item self-report questionnaire including three modules measuring productivity losses of paid work due to 1) absenteeism and 2) presenteeism and productivity losses related to 3) unpaid work in the past 3 months.
3months, 6months, 12 months
Medical costs over 12 months
Time Frame: 3months, 6months, 12 months
Medical costs from a mental health care perspective are assessed using the iMTA Medical Cost Questionnaire (iMCQ). The iMCQ is a 23-item self-report questionnaire, which apart from some general questions include questions on medical consumption from different healthcare providers in the past 3 months.
3months, 6months, 12 months
Change from baseline in health-related quality of life over 12 months
Time Frame: baseline, 2 weeks, 4 weeks, 2 months, 3 months, 6 months, 12 months
Quality of life is measured using the EQ-5D-5L. The EQ-5D-5L scores (reflecting the level of perceived problems on the dimensions of mobility, self-care, usual activities, pain/discomfort and anxiety/depression) are used to calculate utilities using the Dutch tariff. Quality Adjusted Life Years are calculated using linear interpolation between time points. Higher QALY scores indicate more improvement in quality of life.
baseline, 2 weeks, 4 weeks, 2 months, 3 months, 6 months, 12 months
Drop-out rates at post-treatment
Time Frame: 3 or 6 months
Percentage of patiënts who missed more than 25% of CBT sessions.
3 or 6 months
Change from baseline in severity of anxiety symptoms at post-treatment
Time Frame: baseline and 3 or 6 months
Severity of anxiety-related disorder, measured with the following disorder-specific severity questionnaires: the 24-item Liebowitz Social Anxiety Scale self-report version, the 7-item Panic Disorder Severity Scale self-report version, the 28-item Mobility Inventory, the 16-item Penn State Worry Questionnaire, the 10-item Yale-Brown Obsessive Compulsive Scale self-report version, the 20-item PTSD checklist for the DSM-5, or the 14-item Whitely Index. Higher scores indicate higher symptom severity. Z-scores will be calculated from individual scores for group-level analyses.
baseline and 3 or 6 months
Change from baseline in severity of anxiety symptoms at 12 months
Time Frame: baseline and 12 months
Severity of anxiety-related disorder, measured with the following disorder-specific severity questionnaires: the 24-item Liebowitz Social Anxiety Scale self-report version, the 7-item Panic Disorder Severity Scale self-report version, the 28-item Mobility Inventory, the 16-item Penn State Worry Questionnaire, the 10-item Yale-Brown Obsessive Compulsive Scale self-report version, the 20-item PTSD checklist for the DSM-5, or the 14-item Whitely Index. Higher scores indicate higher symptom severity. Z-scores will be calculated from individual scores for group-level analyses.
baseline and 12 months
Patient satisfaction at post-treatment
Time Frame: 3 or 6 months
The 8-item Client Satisfaction Questionnaire (CSQ-8) measures overall satisfaction of the patient with health and human services. Each item on the CSQ-8 is scored from 1 (low satisfaction) to 4 (high satisfaction), possible total scores ranging 8-32.
3 or 6 months
Negative effects of psychotherapy
Time Frame: 3 or 6 months
The 21-item Inventory for the Assessment of Negative Effects of Psychotherapy (INEP) is a self-report instrument for assessing negative effects of psychotherapy from the patient's perspective. The negative effects cover 7 domains: Intrapersonal Change, Intimate Relationships, Stigmatization, Emotions, Workplace, Family and Friends, and Therapeutic Malpractice. The INEP items are answered using a 4-stage response format (0 = "disagree/not applicable"; 3 = "fully agree").
3 or 6 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Investigators

  • Study Director: Neeltje Batelaan, PhD, Amsterdam UMC

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 26, 2024

Primary Completion (Estimated)

November 1, 2026

Study Completion (Estimated)

May 1, 2027

Study Registration Dates

First Submitted

June 16, 2023

First Submitted That Met QC Criteria

July 4, 2023

First Posted (Actual)

July 12, 2023

Study Record Updates

Last Update Posted (Actual)

May 29, 2026

Last Update Submitted That Met QC Criteria

May 26, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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