A Multiple Case Study of Schema Therapy for Difficult-to-treat Depression- DEPRE-ST*Case

This clinical multiple case study seeks to expand the knowledge of how schema therapy could function as an intervention for difficult-to-treat depression. The study will explore in depth the course of a 30 session treatment with schema therapy conducted over approximately one year on three individual patients at two different psychiatric treatment sites.

Together, the data from this study will inform about the feasibility of schema therapy for difficult-to-treat depression as well as form the base for recommendations in adapting schema therapy for this particular patient group.

The study is part of a larger randomized controlled study, the DEPRE-ST study (clinicaltrials.gov registration: NCT05833087)(Arendt et al., 2024). The study participants will also be part of the large trial, and will be recruited for the current case study when their randomization status is being revealed; i.e., they are randomized to schema therapy.

In addition to the data collected in the DEPRE-ST trial, the patients will for each session self-report depression symptoms (before the session) and two different evaluations of the session (after the session). In addition, the patients' level of the schema therapy construct of 'Healthy Adult Mode' will be measured by self-report once monthly.

And finally, the therapist will be interviewed at the end of the treatment course about important aspects of the content and outcome of the therapy. Video recordings of each session will provide detailed information about these aspects and the interventions used in therapy.

The most important focus for the publication for this study will be to describe the trajectories of therapy for the participants, including content, effect, and subjective evaluations of therapists and participants. Also, the feasibility and adaptability of schema therapy for difficult-to-treat depression will be evaluated.

Data from outcome measurements will be presented descriptively only. Interview and video data will be compared with the outcomes measurements to reveal important events and how they might be reflected in the replies to post-session evaluation questionnaires (Session Evaluation Questionnaire and Helpful Aspects of Therapy), and in the course of the participant's self-reported depression symptoms and Healthy Adult mode.

Eligibility Criteria:
Inclusion Criteria:

* Participants have at the time of inclusion been referred to treatment for depression as a primary diagnosis in a psychiatric clinic
* Participants should meet the diagnosis of chronic or treatment-resistant depression as follows:

  1. Clinical major depression as measured by the M.I.N.I. diagnostic interview: duration minimum two years OR persistent after = 2 trials of antidepressants from different classes, in an adequate dosage and time period (= 4 weeks) OR moderate treatment resistance as measured on the MSM-scale, score \> 6
  2. Minimum a score of 9 points on the Hamilton Rating Scale for Depression 6 (HAMD-6), corresponding to moderate to severe depression

Exclusion Criteria:

* Alcohol or substance abuse
* Bipolar or psychotic disorder
* Acute suicidal risk
* Mental disability (estimated IQ \< 70)
* Non-Danish speaker
* Known to be pregnant at time of inclusion

Psychiatric comorbidity is not an exclusion criteria, until the comorbid disorder is understood to be the primary psychiatric problem and as such the patient would be treated in a different care package, e.g., for Post-Traumatic Stress Disorder

(The inclusion and exclusion criteria follow that of the mother study (clinicaltrial.gov ID NCT05833087))