摘要:Background Persons with a past episode of self-harm or severe suicidal ideation are at elevated risk of self-harm as well as dying by suicide. It is well established that suicidal ideation fluctuates over time. Previous studies have shown that a personal safety plan can assist in providing support, when a person experiences suicide ideation, and help seeking professional assistance if needed. The aim of the trial is to determine whether a newly developed safety mobile app is more effective in reducing suicide ideation and other symptoms, compared to a safety plan on paper. Methods/design The trial is designed as a two-arm, observer-blinded, parallel-group randomized clinical superiority trial, where participants will either receive: (1) Experimental intervention: the safety plan provided as the app MyPlan, or (2) Treatment as Usual: the safety plan in the original paper format. Based on a power calculation, a total of 546 participants, 273 in each arm will be included. They will be recruited from Danish Suicide Prevention Clinics. Both groups will receive standard psychosocial therapeutic care, up to 8–10 sessions of supportive psychotherapy. Primary outcome will be reduction in suicide ideation after 12 months. Follow-up interviews will be conducted at 3, 6, 9, and 12 months after date of inclusion. Discussion A safety plan is a mandatory part of the treatment in the Suicide Prevention Clinics in Demark. There are no studies investigating the effectiveness of a safety plan app compared to a safety plan on paper on reducing suicide ideation in patients with suicide ideation and suicidal behavior. The trial will gain new knowledge of whether modern technology can augment the effects of traditional personalized safety planning. Trial registration ClinicalTrials.gov, NCT02877316 . Registered on 19 August 2016.