The Role of Day-to-Day Experiences in Predicting Later Suicidal Ideation and Self-Injury in Young Adults

Suicidality and self-injury in young adults are major public health concerns. Understanding the day-to-day experiences associated with these issues can help identify early risk and/or protective factors. By combining ecological momentary assessment (EMA) with traditional longitudinal assessments, this study aims to better understand the development of suicidal ideation and self-injury from the perspective of daily life experiences in emerging adulthood. Data was drawn from the Decades-to-Minutes (D2M) study, which used an EMA design with four measures per day over a two-week period at age 21, embedded within an existing longitudinal cohort study. EMA measures included negative affect, stress, provocation, substance use, social company, and aggression, along with EMA-derived measures, such as affective lability and reactivity. Suicidal ideation and self-injury were assessed through longitudinal surveys at ages 20 and 24. Two-level dynamic structural equation modelling (DSEM) was employed to examine associations while controlling for earlier suicidal ideation and self-injury. Results showed that only daily cannabis use at age 21 was significantly associated with greater suicidal ideation at age 24. Cross-sectional findings indicated that higher mean levels and variability of negative affect and stress at age 21 were linked to suicidal ideation and self-injury at age 20, and that greater mean levels, stability, and variability of aggression were linked to higher self-injury. These findings highlight the importance of addressing daily cannabis use as a potential long-term risk factor for later suicidal ideation and examining short-term emotional and behavioural dynamics as proximal correlates of suicidality and self-injury in emerging adulthood.