Radically Open Dialectical Behaviour Therapy for Treatment-Resistant Depression: A Randomised Controlled Trial

Even with best treatment one third of patients with major depression do not achieve symptom relief and suicidal behaviour is more likely among those with chronic depression. A major cause of treatment-resistant depression (TRD) is co-morbid personality disorder (PD), present in 40-60% of these patients. The most common PDs reported in these patients are behaviourally over-controlled (obsessive-compulsive, paranoid & avoidant). Depressed PD patients are 4 times more likely to have continuing or relapsing depression than those without PD; they respond poorly to psychotherapies and psychotropic drugs. Standard Dialectical Behaviour Therapy (DBT) has proved to be effective in treating borderline PD. Radically Open DBT (RO-DBT), a new treatment approach with strong roots in standard DBT, has demonstrated promise for patients with difficult-to-treat depression and related overcontrolled disorders. Several studies have informed the development of RO-DBT for TRD, in conjunction with a theoretical model which describes the maintenance of depressive symptoms and the barriers to successful treatment. This theory centers on the role of rigid coping styles, lack of emotional expression and openness, and limited psychological insight. These characteristics, common in TRD patients, limit opportunities for learning new skills, exacerbate aloofness and the belief that the patient is unlovable, and perpetuate constricted patterns of behaviour. Further, the model predicts that negative experiences early in childhood may exacerbate a biological predisposition to heightened threat sensitivity and diminished reward sensitivity, and in turn initiate this over-controlled coping style. We propose a 2-arm, 2-stage, 3-centre RCT of RO-DBT for participants with TRD. All participants will receive treatment as usual (TAU), mainly antidepressant medication, and complete outcome assessments over 18 months. We shall use these assessments to compare combined TAU and RO-DBT lasting 29 weeks with TAU alone. We aim to estimate efficacy and cost-effectiveness of RO-DBT, addressing the effects of both allocation to RO-DBT and receiving RO-DBT (exposure). We propose several innovative adaptations to our RCT to enable us to use cutting-edge statistical methods to estimate the causal effects of mediating variables including treatment-exposure, therapeutic alliance and skill-learning. During stage 1 we shall recruit 26 participants to assess recruitment, adherence and client satisfaction. In stage 2 we shall recruit participants at 3 sites, randomising another 250. The primary outcome depressive symptoms will be measured at randomisation, and 7 , 12 and 18 months later. TL (Southampton), one of the world's leading researchers in RO-DBT, heads our experienced trial team. ITR (Swansea) provides expertise in clinical trials, and PC (Bristol) in causal analysis. Together TL, ITR and PC have been CI or PI on more than 50 RCTs, most in many centres.