Design A mixed-method evaluation of a single-blind randomised controlled trial (RCT) will determine the acceptability and safety of the COPES intervention, in preparation for a future large-scale trial of the efficacy of COPES for depression in people who SH. People who have depression and SH in the community will be randomised to receive either COPES plus treatment-as-usual (TAU) or TAU alone.

Recruitment rates and power calculations This study is intended as a preliminary evaluation of the feasibility of conducting a future large-scale RCT of the COPES intervention. As, the investigators are not conducting any hypothesis testing of effectiveness, or estimation of prevalence (other than attrition) a formal power calculation is not appropriate. A recruitment target of n=60 (n=30 per trial arm) will be used. This is a common and realistic recruitment target for feasibility trials, and will allow adequate precision in estimating rates relevant to trial outcomes (e.g. attrition, adverse events). This will allow an overall attrition rate of 30% to be estimated with 95% confidence intervals of +/- 12% or, 16% for a single arm. This sample size is adequate for estimating relevant analysis parameters, such as the standard deviation of effects, which are needed for determining the feasibility of a later efficacy trial. To avoid high attrition rates, the investigators will keep participants engaged via text and/or telephone reminders. The previous pilot of HOPE within the ED achieved an average recruitment of nine eligible referrals each month. Sixty-one percent of participants engaged with the therapy and attended at least one session. Rates of attendance for SH at GP practices and walk-in centres in the Liverpool area have been estimated at 70 per month. Based on these figures a recruitment rate of 3 to 4 participants each month with a goal of n=60 participants overall is achievable.

Research Sites The research will take place in Liverpool, in the North West of England. The North West has particularly high rates of SH. Between April 2011 and March 2014, there were 16,405 presentations for deliberate SH to emergency departments within Merseyside and Cheshire. Liverpool local authority had one of the highest number of attendances for SH in this area (15%, n = 2,489). Therefore, Liverpool provides a good location for undertaking work on SH.

Recruitment of GP Practices Lead GPs and/or practice managers at practices identified as suitable for inclusion in the COPES study will be invited to take part in writing. Invitation packs will be given by GPs and followed up by a telephone/skype/face time/face-to-face contact from a member of the research team to ascertain level of interest, and if appropriate, to arrange a meeting to discuss the study in more detail. The Clinical Research Network (CRN) will assist with recruitment of GP practices and have provided a letter of support (see Appendix B). Clinicians will be briefed on the COPES trial and provided with guidance on referring patients in to the study. To assist recruitment, clinicians will be provided with a brief screening checklist to help identify patients where depression-linked SH may be a concern.