The aim of this study is to determine whether learning three skills for managing negative emotions and receiving reminders via smartphone to practice these skills reduces how often and how intensely one experiences emotional distress and suicidal thoughts.

The present study is a two-arm parallel design RCT to test the efficacy of using ecological momentary intervention (EMI) to deliver therapeutic content based on the Unified Protocol for the Transdiagnostic Treatment of Emotional Disorders (UP) - an evidence-based transdiagnostic cognitive behavioral therapy (CBT) that focuses on delivering adaptive skills for managing strong emotions. Participants in this study will be 50 adult psychiatric inpatients with recent suicidal thoughts or behaviors (STBs). Participants will be randomized to receive either the control condition, which consists of treatment as usual (TAU; n = 25) and 4x/daily daily ecological momentary assessment (EMA) of emotions and STBs, or the experimental condition, consisting of TAU, 4x/daily EMA, 3 brief sessions to deliver CBT skills (mindful emotion awareness, cognitive flexibility, and changing emotional behaviors, all drawn from the UP), one discretionary skills booster session, and EMI to prompt guided skills practice (n = 25).

Control participants will receive TAU and be prompted to complete 4x/day EMA of emotions and STBs for the duration of their hospital stay and the 28-day post-discharge period. Participants randomized to the experimental conditions will receive TAU plus three brief treatment sessions delivering core UP skills content (during inpatient stays) and a discretionary booster session to reinforce treatment sessions that may be offered after discharge via either phone or telehealth. Those in the experimental condition will also receive training to use the EMI (which prompts guided skills practice), followed by smartphone-based EMA/EMI for the duration of the inpatient stay and the 28-day post-discharge period.

Inclusion Criteria:

• adult status (18+ years),
• a recent suicide attempt or any report of current suicidal ideation,
• the ability to speak and write English fluently,
• ownership of and consistent access to an internet-capable smartphone (e.g., an iPhone or Android phone), and
• providing at least one collateral contact in cases where we cannot reach the participant

Exclusion criteria:

- the presence of any factor that impairs an individual's ability to provide informed consent and comprehend and effectively participate in the study including: an inability to speak or write English fluently, the presence of gross cognitive impairment due to florid psychosis, intellectual disability, dementia, acute intoxication, or the presence of extremely agitated or violent behavior.