Suicide Risk After Social Network Exposure to Suicide Attempts in Adolescents and Young Adults.

Importance: Exposure to suicide thoughts and behaviors within social networks has been associated with suicide risk among adolescents and young adults, but longitudinal evidence examining subsequent suicide attempts, suicidal ideation, and depressive symptoms remains limited. Most prior studies have focused on suicidal ideation or have not accounted for online social engagement. Objective: To examine whether exposure to suicide attempts within one's social network is prospectively associated with suicide attempt onset, suicidal ideation onset, and depressive symptoms in adolescents and young adults. Design, Setting, and Participants: This national longitudinal cohort study used 3 waves of data (baseline, 12 months, and 24 months) from Project Lift Up, a survey of US adolescents and young adults aged 13 to 22 years recruited through social media between June 13, 2022, and October 30, 2023, and followed up for 24 months. Primary analyses included participants without a lifetime suicide attempt at baseline who contributed follow-up data on the main study variables. Exposures: Self-reported exposure to suicide attempts among individuals in participants' social networks, measured at each wave as a lagged construct. Main Outcomes and Measures: The primary outcome was suicide attempt onset during follow-up among participants without a prior suicide attempt. Secondary outcomes included suicidal ideation onset and depressive symptoms. Logistic regression and hybrid mixed-effects models adjusted for demographic characteristics, social network size, and depressive symptoms. Results: Among 2098 participants without a prior suicide attempt at baseline (mean [SD] age, 17.53 [2.26] years; 1259 [60.0%] assigned female sex at birth), exposure to a suicide attempt within one's social network was associated with greater odds of subsequent suicide attempt onset (odds ratio [OR], 2.78; 95% CI, 1.78-4.33). This association remained significant after adjustment for depressive symptoms (OR, 2.43; 95% CI, 1.51-3.91). Exposure was not associated with suicidal ideation onset but was associated with higher depressive symptoms over time (within-person b, 0.13 [95% CI, 0.08-0.17]; between-person b, 0.46 [95% CI, 0.38-0.54]). Larger in-person social networks were associated with fewer depressive symptoms (b, -0.21; 95% CI, -0.25 to -0.17). Conclusions and Relevance: In this cohort study of adolescents and young adults, exposure to suicide attempts within one's social network was associated with subsequent suicide attempt onset and higher depressive symptoms over time. Assessing recent exposure to suicide attempts may help identify youths at elevated suicide risk not detected through symptom-based screening alone.