Non-suicidal self-injury (NSSI), the term used for when somebody purposefully hurts themselves without intending to end their life. Often, it suggests that there are other difficulties going on in someone's life. Talking therapies can be offered to help however currently there is little evidence to show which therapies help most. CATCH-Y (Cognitive Analytic Therapy for Containing Self-Harm in Young People) is a brief talking therapy which has been created to support young people who self-injure. It aims to help young people and those around them build to a shared understanding of their difficulties. Previously a group of adults, who have a history of self-harm, have engaged in a trial version of CATCH-Y for adults, in which it was found to be positive, safe and feasible.

The study will aim to recruit nine young people who have self-injured in the past. Participants must be aged between 13 - 17 years old and have self-injured within the last six months. They will be recruited from local Child and Adolescent Mental Health Services (CAMHS) and associated 3rd sector organisations. The therapy is five sessions long, with two assessment sessions before the therapy begins and one assessment session post-therapy. Online assessments will be completed throughout. CATCH-Y involves working with the therapist to understand a young person's past and current experiences, linked to their self-injurious behaviours. This individualised approach could benefit these young people.

As a novel treatment, and in accordance with the medical research council (MRC) framework, the feasibility and acceptability of CATCH-Y should be considered before progressing to a larger trial. This trial will examine the feasibility and acceptability of the CATCH-Y intervention through attendance and retention rates, data completion and intervention acceptability. As a secondary measure, the trial will investigate whether CATCH-Y shows preliminary evidence for positive change.

Inclusion Criteria:

• Participants will be between the ages of 13 - 17 years.
• Participants will have self-injured at least once in the past six months and have a lifetime history of two or more episodes of NSSI.
• Participants will have a clinician allocated to them within CAMHS or a 3rd sector service.
• Participants will have access to the Internet.

Exclusion Criteria:

• Participants will be excluded if they are currently receiving alternative psychological therapies from a mental health professional. Participants may be receiving other forms of ongoing contact and support that do not constitute a formal psychological therapy.
• Participants will be excluded if they have a severe intellectual disability, which would impair their ability to participate without considerable adaptations being made to the intervention.
• Participants will be excluded if they have inadequate English-language speaking skills due to limitations in their ability to engage with talking therapies in the English language.
• Participants will be excluded if they are judged at high risk of harm to themselves, operationalised as having current suicidal thoughts with a high intent or active plan to end their life.

Given small scale of the study there are no plans to make the data available to other researchers