Psychological therapy for the prevention of suicide in prison: study protocol for a randomised controlled trial

Suicide is the leading cause of preventable death in prisons. Deaths from suicide in prison are significantly, and persistently, elevated compared to those living in the community. Psychological therapies have been shown to be a potentially effective means of alleviating suicidal thoughts, plans and behaviours, but patients located in prison often have no access to evidence-based psychological interventions targeting suicide. The objectives of this programme of research are to investigate the clinical and cost effectiveness of a new psychological therapy programme delivered to male prisoners at risk of suicide.

The PROSPECT trial is a two-armed single blind, pragmatic, randomised controlled trial and will recruit a target sample size of 360 male prisoners, identified as at-risk of suicide, across 4 prisons in the North of England. Participants will be randomised to receive a psychological talking therapy (Cognitive Behavioural Suicide Prevention, CBSP) plus treatment as usual, or treatment as usual alone. Co-primary outcomes (Suicide Ideation and Suicide Behaviours), as well as related secondary outcomes, will be assessed at baseline and at 6-months follow-up. An intention to treat analysis will be conducted with primary stratification based on prison site and lifetime history of suicide attempt (yes/no). A nested qualitative process evaluation will investigate the nature and context in which the intervention is delivered, with specific focus upon the facilitators and barriers to the implementation of the therapy within prisons.

The key outputs from this trial will be to determine whether a psychological therapy for suicidal prisoners is clinically and cost effective; and to generate a project implementation platform that identifies how best to implement the new intervention across the broader prison estate.

ISRCTN (reference ISRCTN14056534 https://www.isrctn.com/ISRCTN14056534 ; 24th September 2021). Registration confirmed prior to participant recruitment commencing. Modifications to protocol are listed on the study website at ISRCTN.