There are few interventions that directly address self-harming behaviour among adolescents. At the request of clinicians in Child and Adolescent Mental Health Services (CAMHS) in England and working with them, we redeveloped an adult SMS text-messaging intervention to meet the needs of adolescents under the care of CAMHS who self-harm. | Implementation of a text-messaging intervention for adolescents who self-harm (TeenTEXT): A feasibility study using normalisation process theory