Schema Therapy for Treatment-resistant Anxiety Disorders

The aim of this study is to assess the cost-effectiveness of schema therapy compared to treatment as usual (TAU) in patients with treatment-resistant anxiety disorders. In a multicenter randomized controlled trial, patients will be assigned to receive individual schema therapy (maximum of 40 sessions) or treatment as usual (control group) within one year. The primary outcome is the difference between ST and TAU conditions in anxiety symptoms as measured with the Beck Anxiety Inventroy (BAI) at post treatment. Secondary outcomes include quality of life, societal costs, general mental health, remission from the anxiety disorders and/or comorbid affective disorders, positive and negative effects of psychotherapy, schemas and schema modes, and satisfaction. Measurements take place at baseline and after 1, 3, 6, 12, 24 and 36 months (follow-up of two years).

RATIONALE Although treatment for anxiety disorders is generally (cost-)effective, a significant proportion of 30 to 60% of patients does not adequately respond to first-line treatments (i.e. cognitive behavioral therapy (CBT) and antidepressants). This patient group remains significantly impaired. A next-step psychotherapy focusing on underlying vulnerability is urgently needed.

OBJECTIVE To evaluate the cost-effectiveness of individual schema therapy (max. 40 sessions) versus treatment as usual in patients with treatment-resistant anxiety disorders from a societal perspective.

STUDY DESIGN Multicenter randomized controlled trial with a cost-effectiveness analysis and an embedded process evaluation. The project title "PaDoLA" refers to "PAtronen DOorbreken bij Langdurige Angst" in Dutch, which translates to "breaking patterns in chronic anxiety".

STUDY POPULATION Adults (18-65 years) with treatment-resistant DSM-5 anxiety disorders recruited in specialized mental health care. Treatment-resistance is defined as (at least) one failed trial of \> 8 weeks CBT plus one failed trial of a serotonergic antidepressant for \> 8 weeks plus persistence of anxiety symptoms.

INTERVENTION Intervention group: Individual schema therapy with max. 40 sessions within one year. Schema therapy is an integrative psychotherapy, with a high emphasis on the therapeutic relationship ("limited reparenting"), use of trauma focused techniques, experiential and cognitive techniques, role-play and behavioral exercises. The treatment protocol used in this study is adapted specifically for patients with treatment-resistant anxiety disorders.

Control group: Treatment as usual (TAU) described by the Dutch Quality Standard for Anxiety disorders. As there is no gold standard psychotherapy for treatment-resistant anxiety disorders, professionals often offer (extended or intensified) CBT and/or pharmacological treatment in TAU. The only restriction to TAU is that schema therapy may not be provided.

MAIN STUDY PARAMETERS/ENDPOINTS:

Primary outcome is the difference in anxiety symptoms as measured with the BAI at post treatment. Primary outcomes for the cost-effectiveness analysis are anxiety symptoms, quality of life and (societal) costs. Measurements take place at baseline and after 1, 3, 6, 12, 24 and 36 months. Secondary outcomes are general mental health, remission from the anxiety disorders and/or comorbid affective disorders, positive and negative effects of psychotherapy, schemas and schema modes, and satisfaction. Alongside the RCT, a process evaluation is performed to gain insight in experiences of patients and provide suggestions for implementation.

SAMPLE SIZE/DATA ANALYSIS A total of 172 patients will be enrolled (assuming a medium effect size d=0.5, testing two-sided using at ɑ=0.05, power = 0.80) including adjustment for an anticipated 25% dropout. We will perform an intention-to-treat analysis using a linear mixed model.

COST-EFFECTIVENESS ANALYSIS A cost-effectiveness and cost-utility analysis will be performed to compare effects on anxiety symptoms, quality of life and costs from a societal perspective including health care costs and productivity costs.

TIME SCHEDULE Study duration is 7 years: the first four years preparations will be made, patients will be included and treated. The follow-up phase of 2 years is necessary because effects are expected to be most prominent in the long term. Implementation efforts will be continuous during the study period.

Eligibility Criteria:
Inclusion Criteria:

* Primary diagnosis of an anxiety disorder (panic disorder, agoraphobia, social anxiety disorder, generalized anxiety disorder, separation anxiety disorder and specific phobia) based on the Diagnostic and Statistical Manual of Mental Disorders (DSM-5).
* Fulfilling the criteria of treatment-resistance based on a systematic literature search by Bokma and collegues: i) at least one unsuccessful CBT treatment of ≥ 8 weeks; and ii) at least one unsuccessful pharmacological treatment with a serotonergic antidepressant of ≥ 8 weeks, and iii) moderate to severe anxiety symptoms (BAI \> 11). The adequacy of previous treatment will be checked.

Exclusion Criteria:

* Substance use dependence
* Acute suicidality
* Has received schema therapy in the past
* Has insufficient language skills in Dutch and/or English