Predicting high perceived stress in late adolescence: development and validation of a prognostic model

AIM: Stress levels have increased among adolescents, yet tools for identifying those at high risk remain limited. This study aimed to develop and internally validate a prognostic model estimating the probability of high perceived stress in young adulthood using data collected at age 15. METHODS: Data were from the West Jutland Cohort Study including 2,108 Danish adolescents with complete information on the 4-item Perceived Stress Scale at ages 15 and 18. High stress at age 18 was defined as a total score of 9 or higher. Twenty-three candidate predictors were examined using Least Absolute Shrinkage and Selection Operator (LASSO) regression across 100 imputed datasets. Predictors selected in ≥ 80% of imputations were entered into a pooled logistic regression model. Model performance was evaluated using 10-fold cross-validation under multiple imputation. Discrimination was assessed with the area under the receiver operating characteristic (ROC) curve (AUC), and calibration with calibration-in-the-large (CITL) and slope. RESULTS: Three predictors at age 15 were retained: perceived stress, depressive symptoms, and self-esteem. The model showed good calibration (CITL = 0.003; slope = 1.008; expected-to-observed ratio = 0.998) and acceptable discrimination with an AUC = 0.72 (0.68;0.76). The Brier score was 0.081, indicating satisfactory overall predictive accuracy. The model showed high negative predictive values but modest positive predictive values. CONCLUSIONS: A simple model based on self-reported psychosocial measures in mid-adolescence predicted later high stress with good calibration and moderate discrimination. External validation is needed to assess generalisability and inform potential use as a low-burden decision-support tool in school health settings.