Joint Trajectories of Depression and Rumination: Experiential Predictors and Risk of Nonsuicidal Self-Injury

Objective: Nonsuicidal self-injury (NSSI) is common in adolescence. Rumination is a key risk factor and often co-occurs with depressive symptoms. This is the fi rst study to examine the joint longitudinal trajectories of rumination and depressive symptoms as predictors of NSSI, and the adverse experiences associated with these trajectories. Method: A community sample of 1,835 adolescents (55.9% male participants, 12.3 +/- 0.5 years of age) completed questionnaires to assess adverse childhood experiences, rumination, depressive symptoms, and NSSI. Assessments were made 4 times over 18 months. Results: A parallel process growth mixture model showed that youth with high trajectories of rumination but low trajectories of depression had moderately increased odds of NSSI (2.43-fold, 95% CI 1.53-3.91) compared with adolescents with low trajectories of both rumination and depression. Odds ratios (ORs) in adolescents with low trajectories of rumination but increasing or high trajectories of depression were similarly elevated, suggesting that high trajectories of rumination or depression were risk factors in isolation. However, odds were 10.06-fold greater (95% CI 5.68-18.02) when high trajectories of rumination occurred in tandem with high trajectories of depression. Multinomial logistic regression showed that male sex (OR 10.54, 95% CI 5.66-19.63), peer victimization (OR 2.25, 95% CI 1.72-2.96), and parental alienation (OR 1.94, 95% CI 1.46-2.57) were key determinants of membership in the highest risk group. Conclusion: Risk for NSSI is markedly increased in adolescents with high longitudinal trajectories of depression and rumination. Reducing exposure to peer victimization, cyber victimization, emotional abuse, parental alienation, and interparental conflict may reduce risk. Plain language summary: The authors of this study conducted a longitudinal analysis of 1,835 adolescents in the Peoples Republic of China to evaluate rumination and depressive symptoms as predictors of nonsuicidal self-injury. The authors found that high trajectories of either rumination or depression alone was associated with an elevated risk of nonsuicidal self-injury. The combination of high trajectories of both rumination and depression resulted in the highest risk. Male sex, peer victimization, cyber victimization, and parental alienation were more common in the highest trajectory risk groups.