Life Event Trajectories and Suicidal Ideation throughout Adolescence:A Multinational Prospective Cohort Study

Background<br/>Adolescence is a sensitive period when suicidal ideation first peaks. While traumatic life events are a well-established risk factor, the role of cumulative ordinary life events across multiple dimensions such as family, autonomy, sexuality remains underexplored. Crucially, there is currently no evidence on how multidimensional trajectories of cumulative exposure to such events relate to suicidal ideation throughout adolescence. The aim of this analysis using a multinational, longitudinal cohort was to determine how cumulative and domain-specific trajectories of ordinary life events during adolescence predict suicidal ideation, with particular emphasis on the impact of the family dimension.<br/><br/>Methods<br/>We included longitudinal data from the IMAGEN cohort (n=2,161 adolescents assessed at ages 14, 16, 19, and 23) to model trajectories of exposure to all life events across seven dimensions (Family, Accidents, Distress, Autonomy, Deviance, Sexuality, and Relocation) from adolescence to young adulthood, and quantified the association between trajectory membership and suicidal ideation throughout adolescence, adjusting for childhood maltreatment, sex, parental education, and ethnicity. <br/>The IMAGEN cohort is a multinational, longitudinal study conducted across eight centers in major cities in Germany, the United Kingdom, Ireland, and France. Participants were enrolled during early adolescence and underwent repeated assessments through young adulthood. Key inclusion criteria were: age 12–14 at enrollment; capacity to provide informed assent/consent; and parental ability to provide complete perinatal and developmental history. <br/>Exposure to life events was assessed using the Life Events Questionnaire (LEQ), administered at each of the four study timepoints (ages 14, 16, 19, and 23). The LEQ is a validated instrument that assesses the occurrence of 39 ordinary life events across seven psychosocial domains (Family, Accidents, Distress, Autonomy, Deviance, Sexuality, and Relocation) within the prior year or relevant interval. Childhood maltreatment was assessed with the Childhood Trauma Questionnaire (CTQ), a 28-item scale capturing five types of maltreatment (physical abuse, emotional abuse, sexual abuse, physical neglect, and emotional neglect), administered once at age 19. Suicidal ideation was the primary endpoint, assessed via a dedicated item in the Life Events Questionnaire (LEQ) at the first three study waves (ages 14, 16, and 19).<br/>Latent trajectory analysis was used to identify classes of cumulative life event exposure across repeated assessments. The association between trajectory group membership and suicidal ideation was quantified using logistic mixed model regressions, adjusting for demographic and maltreatment covariates.<br/>No individuals with lived experience of suicidality or mental health conditions were involved in the design, conduct, or reporting of this research.<br/>Findings<br/>At baseline, 2,161 adolescents were included in the cohort (female: 1,106 [51%], male: 1,055 [49%]). Sample sizes at subsequent waves were 1,581 (FU1), 1,474 (FU2), and 1,331 (FU3). Latent trajectory analysis identified four trajectories of cumulative life events loads: “High”, “Mid-High”, “Mid-Low” and “Low”. Family and Sexuality dimensions were key in classifying the “High” trajectory. Participants in the High life events trajectory had a significantly higher predicted probability of experiencing suicidal ideation throughout adolescence, compared to those in the other life events trajectory groups. Furthermore, life events in the Family dimension predicted adolescent suicidal ideation (marginal R2glmm = 0·078) more than those in all remaining dimensions combined (marginal R2glmm = 0·073). <br/>Interpretation<br/>Higher cumulative exposure to ordinary life events across multiple dimensions is associated with higher suicidal ideation in adolescence, with life events occurring within the family environment carrying a unique higher risk. These results point to the importance of evaluating different types of everyday life event exposure, and not just childhood trauma or maltreatment when assessing suicidal risk in adolescents, and emphasizes the use of a dimensional approach in understanding the impact of everyday life events on adolescent suicidality.