This study is testing whether it is feasible to run a larger randomized controlled trial and whether an automated text messaging program is acceptable to young adults who have suicidal thoughts. The program is designed to help participants create and use a safety plan, which is a personalized list of warning signs, coping strategies, supportive people, professional resources, ways to make their environment safer, and reasons for living. After joining and completing an initial survey, participants are randomly assigned by a computer to one of two groups. One group starts right away with the interactive safety planning text program. The other group first receives simple text messages with 24/7 crisis resources and then, after four weeks, also receives the interactive safety planning program. Participants use the text program for about four weeks and complete online surveys at the start and again over a total period of 24 weeks.

This study is a randomized, controlled feasibility trial testing an automated text messaging program designed to help young adults (ages 18 to 24) who have recently experienced suicidal thoughts create and use a personalized safety plan. A safety plan is a step-by-step list of warning signs, coping strategies, supportive people, professional resources, ways to make the environment safer, and personal reasons for living that can be used during times of crisis. The main goals of the study are not to prove effectiveness or efficacy, but to determine whether it is possible to run a larger randomized controlled trial in the future and whether young adults find this type of text-based safety planning acceptable, usable, and engaging.

Sixty participants will be enrolled from across the United States through Mental Health America and online outreach. After completing screening, providing consent, finishing baseline surveys, and confirming they can receive text messages, participants will be randomly assigned by a computer, like flipping a coin, to one of two groups. Neither participants nor study staff choose the group assignment. One group will receive the interactive safety-planning text program right away. The other group will first receive supportive but non-interactive text messages that provide 24/7 crisis resources, and after four weeks will also begin the same interactive safety-planning program. This "enhanced waitlist" design allows all participants to eventually receive the intervention while still allowing researchers to compare early outcomes between groups.

The interactive program lasts four weeks and sends daily text messages that guide users through building and practicing their safety plan. Messages ask participants to reflect on their own experiences, write responses in their own words, identify coping activities, supportive people, crisis services, and ways to reduce access to dangerous means. The system uses follow-up questions and branching logic so that each person's safety plan becomes detailed and highly personalized. Participants can also review and update their plan through a secure web link and can request different modules on demand. After the four-week active phase, participants can continue to access their safety plan for the rest of the 24-week study period.

Throughout the study, participants complete online surveys at the start and again at 2, 4, 8, 16, and 24 weeks. These surveys measure suicidal thoughts and behaviors, coping skills, emotional pain, hopelessness, social connection, and how acceptable and helpful the text program feels. A key focus is whether participants stay engaged, complete assessments, and find the intervention useful and safe, which are critical indicators of feasibility and acceptability for a future larger trial.

Inclusion Criteria:

1. Ages 18 to 24 *The age to provide consent in Nebraska is 19. Individuals recruited from the state of Nebraska must be 19 or older.
2. endorsement of past 2-week suicidal ideation
3. Resident of the United States
4. Owns a smartphone

Exclusion Criteria:

1. Serious mental illness for which intervention would be contraindicated (i.e., active psychosis or mania)
2. Imminent suicidality (i.e., experiencing active suicidal ideation with a plan and intent to act)
3. Written English language skills that are insufficient to engage in the consent, design, evaluation, or intervention procedures.