Cost-effectiveness of schema therapy for treatment-resistant anxiety disorders: A multicentre RCT

1 in 4 Dutch citizens will experience an anxiety disorder at least once in
their lifetime. Unfortunately, standardized treatments (such as cognitive
behavioural therapy (CBT) and medication) are ineffective for 30-60% of
patients. When the anxiety disorder persists despite treatment, we refer to it
as treatment-resistant. Schema therapy focuses on adjusting beliefs (schemas)
and survival strategies formed early in life that are related to the
persistence of anxiety symptoms. Schema therapy has highly positive and
long-lasting effects in individuals with personality disorders. It also seems
to work well for treatment-resistant anxiety disorders, but it remains unclear
whether this treatment is cost-effective. In this randomised controlled trial
amongst 172 patients with treatment-resistant anxiety disorders, half of the
patients will receive a maximum of 40 sessions of individual schema therapy
(ST), while the other half will receive usual care (UC; often a continuation of
CBT or medication). We will compare the effectiveness of both treatments on
anxiety symptoms, quality of life and societal and health care costs. We expect
ST to be superior to UC in terms of reduction of anxiety symptoms and improved
quality of life, against lower social costs, especially in the longer term (24
to 36 months).

The primary objective of this study is to evaluate the cost-effectiveness of
individual ST (max. 40 sessions) vs. UC in patients with treatment-resistant
anxiety disorders from a societal perspective. The second objective is to
explore whether certain patient characteristics are related to the
effectiveness of ST (e.g., gender, ethnic background, or the presence of a
comorbid depression/personality disorder/autistic characteristics). The third
objective is to promote implementation by gaining insight into how patients and
their relatives evaluate ST, assess fidelity to ST, and identify factors that
influence implementation to inform implementation beyond the trial context
(process evaluation).

A multicentre RCT with a cost-effectiveness analysis and an embedded process
evaluation.

Patients will be randomized to the intervention group (schema therapy; ST) or
the control group (usual care; UC). ST is an integrative psychotherapy, with a
high emphasis on the therapeutic relationship (*limited reparenting*), use of
trauma focussed techniques, experiential and cognitive techniques, role-play
and behavioural exercises to improve the ability of patients to have their
emotional needs met. The ST treatment protocol used in this study is adapted
specifically for patients with treatment-resistant anxiety disorders based on
observational studies conducted at GGZ inGeest and Propersona. Especially in
the second half of treatment emphasis is placed on exposure to feared
situations. Although exposure is also part of CBT, the essential difference is
that the exposure is integrated in ST and introduced following addressing the
underlying maladaptive schemas and personality factors that form a barrier to
profit from exposure. Individual schema therapy consist of a maximum of 40
sessions within 1 year.

Usual care is optimal care following the Quality Standard for anxiety
disorders. As there is no gold standard psychotherapy for treatment-resistant
anxiety disorders, UC often consists of another trial of CBT and medication,
but may also be another form of treatment offered by the participating centres.
There are no restrictions to UC, except that it may not be ST. Actual content
of UC will be tracked.

Schema therapy is included in the multidisciplinary guidelines for treating
personality disorders and is found to be safe and effective. In regular care,
shcema therapy is provided for patients with various disorders, also in
vulnerable groups (i.e. patients with borderline personality disorder). We
expect negligible risks of participating in ST based on earlier studies. Schema
therapy may evoke emotional responses, especially at the start of treatment and
during exposure. However, these emotions are needed to achieve lasting changes
and the patient will be supported by the therapist during difficulties.
Moreover, a relative will be invited in the beginning of the therapy, to
collaboratively inform the patient and his or her relative about what to expect
in schema therapy and how to cope with any upcoming emotions related to the
therapy. In both conditions, patients are asked to complete several interviews
and questionnaires, which are a time investment of in total 9.3 hours spread
out over 3 years. The several questionnaires and interviews may be emotionally
challenging for some patients, as they are being confronted with their anxiety
symptoms. To ensure that the measurement occasions are as comfortable as
possible, patients may take breaks or continue the measurements at a later
point in time. Patients will be financially compensated for their time (max. 15
euros per questionnaire). The participant will receive support from their
therapist, the principal investigator (clinical psychologist) or the PhD
student (psychologist) when needed. UC is standard care and therefore a
negligible risk is expected.