Introduction Self-harm is a strong predictor for suicide. Risks for repeat behaviour are heightened in the aftermath of an index episode. There is no consensus on the most effective type of intervention to reduce repetition. Treatment options for patients who do not require secondary mental health services include no support, discharge to general practitioner or referral to primary care mental health support services. The aim of this study is to assess whether it is feasible to deliver a brief intervention after an episode and whether this can reduce depressive symptoms and increase the sense of well-being for patients who self-harm.

Methods This is a non-blinded parallel group randomised clinical trial. 120 patients presenting with self-harm and/or suicidal ideation to mental health services over a 12-month period who are not referred to secondary services will be randomised to either intervention plus treatment as usual (TAU), or control (TAU only). Patients are assessed at baseline, 4 and 12 weeks with standardised measures to collect data on depression, well-being and service use. Primary outcome is depression scores and secondary outcomes are well-being scores and use of services. The findings will indicate whether a rapid response brief intervention is feasible and can reduce depression and increase well-being among patients who self-harm and do not require secondary services.

Ethics and dissemination Ethical approval was granted by the UK National Health Service (NHS) Ethics Committee process (REC 6: 14/WA/0074). The findings of the trial will be disseminated through presentations to the participating Health Board and partners, peer-reviewed journals and national and international conferences.

Trial registration number ISRCTN76914248; Pre-results.