A definitive randomised controlled trial of a group mindfulness-based psychological therapy for people with psychosis: the MIND-P study

Abstract Background Schizophrenia is a severe mental illness with a significant disease, economic and social burden. Persecutory delusions (beliefs that one will be harmed or mistreated) are a common symptom of schizophrenia with associated high levels of depression. International clinical guidelines recommend individual cognitive behaviour therapy for schizophrenia, but there are currently no group psychological therapies recommended in NICE guidelines. We conducted a pilot randomised controlled trial, comparing group mindfulness therapy (GMT) to treatment as usual (TAU) for people with schizophrenia and persecutory delusions where we demonstrated feasibility and acceptability. It is now timely to progress to conduct a definitive randomised controlled trial (RCT). Methods A parallel group RCT with single blind assessment comparing GMT + TAU (intervention condition) with TAU alone (control condition). The PHQ-9 and additional patient-reported psychometric measures will be collected at three time points: at baseline (prior to randomisation), end of therapy (approx 4 months post randomisation), and follow up (approx 8 months post-randomisation). Participants will be 144 adults with a schizophrenia spectrum diagnosis with current persecutory delusions or attending an early intervention in psychosis service, recruited across 3 NHS sites (Hampshire and Isle of Wight Healthcare NHS Foundation Trust, Greater Manchester Mental Health NHS Foundation Trust, and Pennine Care NHS Foundation Trust), randomised 1:1 to intervention or control groups. The therapy will be delivered according to our published manualised protocol. We will also monitor and evaluate a range of safety indices throughout the trial, conduct mediation and moderation analyses to understand how, and for whom, the therapy is most effective and assess cost effectiveness. Discussion If shown to be effective and cost-effective, GMT will positively impact the lives of people with schizophrenia, by providing an evidence-based group therapy. This is particularly important as there are no group psychological therapies for schizophrenia in the NICE guidelines and group therapies offer the potential for cost savings for service providers. The findings will be disseminated to a range of stakeholders, including service users/carers, academic researchers, clinicians, research participants and the general public, via academic publications, conferences, plain English summary (written and video versions) and public engagement events. Trial registration ISRCTN: ISRCTN16318074, registered on 07/02/2025.