Accelerating the development of a psychological intervention to restore treatment decision-making capacity in patients with schizophrenia-spectrum disorder: An umbrella trial.

INTRODUCTION

Many individuals with schizophrenia-spectrum disorder ('psychosis') lack capacity to make decisions about psychiatric treatment ('incapacity'), however we lack robust evidence from clinical trials on interventions to improve it. To accelerate their development, we tested whether an 'umbrella' trial was feasible. This involved running multiple randomised controlled 'interventionist-causal' trials (IC-RCTs) concurrently. Each tested the effect on incapacity of targeting an individual psychological mechanism.

METHODS

We did 3 assessor-blind, multi-site, pilot IC-RCTs. Each compared 6 sessions of psychological therapy for either self-stigma (SS), low self-esteem (SE) or the jumping-to-conclusions (JTC) bias, to 6 sessions of collaborative assessment of the causes of incapacity (control). Adults with psychosis, incapacity and ≥1 target mechanism could participate. Primary outcomes were recruitment feasibility, and data retention on the MacArthur Competence Assessment Tool-Treatment (MacCAT-T).

RESULTS

We recruited 57 participants and performed 60 randomisations (3 patients participated in 2 trials); 82 % provided post-treatment data. Standardised mean differences (Hedges' g) for MacCAT-T 'understanding' were g = 0.35 (SS; 95 % CI -0.51, 1.22), g = 0.41 (JTC; -0.55, 1.38) and g = 0.74 (SE; -0.73, 2.21), with positive values favouring treatment. For 'reasoning', they were -0.20 (SS; -1.05, 0.66), 0.79 (JTC; -0.20, 1.79) and 0.79 (SE -0.69, 2.27). For 'appreciation' they were -0.39 (SS; -1.25, 0.48), 1.76 (JTC; 0.62, 2.90) and 0.57 (SE; -0.87, 2.02). Four control participants had 9 serious adverse events between randomisation and post-treatment; two intervention participants had 2.

DISCUSSION: An umbrella trial of psychological interventions to improve capacity in psychosis is feasible. A definitive trial is warranted.

TRIAL PRE-REGISTRATION: NCT04309435.