DEcision-making Capacity: Intervention Development & Evaluation in Schizophrenia-spectrum Disorder

Treatment decision-making capacity ('capacity') refers to a person's ability to make decisions about their treatment. It is an important issue for people diagnosed with a schizophrenia-spectrum disorder ('psychosis') because impaired capacity can mean a person does not understand what treatment options are available, or the implications of those options. In 2018 the National Institute of Health \& Care Excellence (NICE) called for clinical trials of interventions such as talking therapies to help people regain capacity. However, running these trials can take several years. One way of reducing this delay is to run several trials at the same time, as part of one bigger trial called an 'Umbrella' trial. Although Umbrella trials have been used to accelerate the development of physical health interventions, they have yet to be used in mental health. The main aims of this study are therefore to find out whether people with non-affective psychosis (schizophrenia-spectrum disorder) will take part in a single (rater) blind Umbrella trial of talking therapies to improve their treatment decision-making capacity (the DEC:IDES trial), and to understand their experiences of participation. Before a larger version of the DEC:IDES trial can begin, it needs to be established that people with psychosis will want to take part in it. Specifically, the aim of this study is to establish whether they will stay in the trial until it is finished, or whether they will leave early. It will also examine why people might leave DEC:IDES early, so that it can be improved. For these reasons, a smaller version must be completed first. This will involve 3 small clinical trials, each with N=20 (Treatment N=10; Control N=10), each testing 1 of 3 different interventions. Each intervention has been designed to help participants resolve a problem which previous evidence suggests may reduce their decision-making ability. One intervention is designed to improve self-esteem, another is designed to reduce