A Randomized Controlled Trial of a Smartphone Delivered Treatment for Suicidal Thoughts and Behavior

Inclusion Criteria: * Adults ages 18+ * Relatively frequent and recent (≥5 days within the past-month) active suicidal thoughts as assessed via SITBI-R. * Willing and able to provide at least one emergency contact (name, phone number, relation). * Owns an Android or iOS smartphone. * Possesses at least occasional access to Wi-Fi-enabled internet for data down/uploads. * Fluent in English and willing to provide informed consent. * Living in the Boston metropolitan area (i.e., \~50 mile radius around Boston, MA) Exclusion Criteria: * Recent (past 3-month) hypo/manic symptoms or homicidal ideation or lifetime psychosis spectrum diagnosis as assessed via MINI 7.0.2. * Recent acute suicide risk operationalized as affirmative responses to BOTH below items during structured clinical interview AND evaluation by the PI in consultation with Mentors/Advisor Drs. Wilhelm, Kleiman, and/or Bentley: * At any time in past week: ≥ 8/10 current intent to act on suicidal thoughts (0 \["not at all"\] to 10 \["extremely strong"\]); AND * At any time in past week: thought of a specific suicide plan (i.e, known method/means and/or location) with access to lethal means * Impaired vision (e.g., legal blindness), technological illiteracy, or intellectual disability that might impair ability to provide valid data and/or informed consent.