Five-year follow-up of the iBerry Study: screening in early adolescence to identify those at risk of psychopathology in emerging adulthood

The iBerry Study, a Dutch population-based high-risk cohort (n = 1022) examines the transition from subclinical symptoms to psychiatric disorders in adolescents. Here, we present the first follow-up measurement, approximately 3 years after baseline assessment and 5 years after the screening based on self-reported emotional and behavioral problems (SDQ-Y). We give an update on the data collection, details on the (non)response, and the results on psychopathology outcomes. The first follow-up (2019-2022) had a response rate of 79% (n = 807). Our results at baseline (mean age 15.0 years) have shown the effectiveness of using the SDQ-Y to select a cohort oversampled for the risk of psychopathology. At first follow-up (mean age 18.1 years), the previously administered SDQ-Y remains predictive for selecting adolescents at risk. At follow-up, 47% of the high-risk adolescents showed significant mental health problems based on self- and parent reports and 46% of the high-risk adolescents met the criteria for multiple DSM-5 diagnoses. Compared to low-risk adolescents, high-risk adolescents had a sevenfold higher odds of significant emotional and behavioral problems at follow-up. Comprehensive assessment on psychopathology, substance abuse, psychotic symptoms, suicidality, nonsuicidal self-injury, addiction to social media and/or video gaming, and delinquency, as well as social development, and the utilization of healthcare and social services were conducted. This wave, as well as the ones to follow, track these adolescents into their young adulthood to identify risk factors, elucidate causal mechanisms, and discern pathways leading to both common and severe mental disorders. Results from the iBerry Study will provide leads for preventive interventions.