Acceptance and Commitment Therapy Versus Cognitive Therapy for the Treatment of Major Depressive Disorder

Study Overview
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Brief Summary
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The study will investigate the effectiveness of Cognitive Therapy and Acceptance and Commitment Therapy in a randomized controlled trial among patients with Major Depressive Disorder in routine clinical practice. Furthermore, the study will investigate whether each specific treatment approach is mediated by its proposed theoretical mechanism.

Detailed Description
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The current study aims at investigating the effectiveness of Cognitive Therapy and Acceptance and Commitment Therapy in a randomized controlled trial among patients with MDD in routine clinical practice. Further, the study will investigate whether each specific treatment approach is mediated by its proposed theoretical mechanism. Patients have to meet diagnostic criteria for nonpsychotic MDD as determined by the Structured Interview for DSM-IV. Each client will receive either Cognitive Therapy or Acceptance and Commitment Therapy that will last between 16 to 20 sessions. Based on previous results, it is expected that both treatment forms will prove beneficial for the patients.

Official Title
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Acceptance and Commitment Therapy vs. Cognitive Therapy for the Treatment of Major Depressive Disorder

Conditions
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Major Depressive Disorder

Intervention / Treatment
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* Behavioral: Cognitive Therapy
* Behavioral: Acceptance and Commitment Therapy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Meeting DSM-IV criteria for MDD Between the ages of 18 and 65-years-old Having sufficient fluency in Dutch to complete treatment and research protocol Exclusion Criteria: DSM-IV criteria for bipolar disorder (past or present) Psychotic disorders Substance dependence disorders (current or within the past 6 months), or Organic brain syndrome. Borderline or antisocial personality disorder

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Cognitive Therapy (CT)<br>Cognitive Therapy (CT) | Behavioral: Cognitive Therapy<br>* This interventions will target: (a) behavioral dysfunction, (b) situation-specific negative thinking and cognitive distortions, and (c) underlying dysfunctional beliefs or cognitions assumed to be related to the patient's current depression and risk of future depression. A maximum of 20 45-55 minute sessions will be provided, with sessions generally held weekly for the first 8 sessions and once every two weeks for the next 8 sessions.<br>* Other names: Cognitive behavior therapy; cognitive behaviour therapy.;|
| Experimental: Acceptance and Commitment Therapy (ACT)<br>Acceptance and Commitment Therapy (ACT) | Behavioral: Acceptance and Commitment Therapy<br>* This interventions will use (a) acceptance, (b) commitment, (c) mindfulness, and (d) behavior change processes to produce reduction of depressive symptoms. A maximum of 20 45-55 minute sessions will be provided, with sessions generally held weekly for the first 8 sessions and once every two weeks for the next 8 sessions.<br>* Other names: Mindfulness-based interventions;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| QUICK INVENTORY OF DEPRESSIVE SYMPTOMATOLOGY (QIDS-SR) | Change from pre-treatment to post-treatment, 6 months follow-up and 12 months follow-up | pre-treatment, post-treatment, 6 and 12 months follow-up | 
| Hamilton Rating Scale for Depression | Change from pre-treatment to post-treatment. | pre-treatment, post-treatment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Decentering subscale of the Experiences Questionnaire | Change between sessions and to follow-up. | Pre-treatment, in-treatment, and 6 and 12 months follow-up. | 
| Acceptance and Action Questionnaire | Change between sessions and to follow-up. | Pre-treatment, in-treatment, and 6 and 12 months follow-up. | 
| Dysfunctional Attitude Scale-revised | Change between sessions to follow-up. | Pre-treatment, in-treatment, and 6 and 12 months follow-up | 
| Working Alliance Inventory |  | 3. session | 
| Eurohis Quality of Life Scale | Change pre-treatment to post-treatment and to follow-up. | Pre-, post-treatment, 6 and 12 months follow-up | 
| Relationship Scales | Change pre-treatment to post-treatment and to follow-up. | Pre-, post-treatment, 12 months follow-up | 
| Implicit Attitude Test | Change pre-treatment to post-treatment | Pre- and posttreatment | 
| Structured Clinical Interview for DSM-IV (Major Depression Module) | Change in diagnosis of Major Depression Disorder from pre-treatment to post-treatment. | Pre-treatment and post-treatment. |