Depression as a Longitudinal Modulator of Physical–Verbal Aggression in Early Adolescence: Trajectories and Sex Comparisons

Background:
Depression in early adolescence has been increasingly linked to heightened aggressive behaviour, yet little is known about how depressive symptoms shape the developmental trajectory of physical–verbal aggression during this critical period. Early adolescence (ages 10–14) is marked by the onset of sex differences in depression as well as significant changes in externalising behaviours, making it an essential stage for understanding comorbidity patterns. This study examines whether depressive symptoms function as a chronic and dynamic risk factor for aggression and whether these effects differ by sex.
Objective:
(1) To analyse the longitudinal effect of depression on physical–verbal aggression across early adolescence;
(2) To determine whether sex moderates the developmental trajectory and severity of aggression in adolescents with and without depression.
Method:
A three‑wave longitudinal design was conducted with 251 adolescents (66.5% girls; ages 10–14) recruited through random probability sampling in Madrid, Spain. Depression was assessed using the CDI‑S, and physical–verbal aggression with the PVA. Repeated‑Measures ANOVA tested intra‑ and inter‑individual differences across ages 10.8 (T1), 11.8 (T2), and 12.8 (T3), including sex and depression status as between‑subjects factors.
Results:
Depression exerted a significant longitudinal effect on aggression (F(1,249)=14.54, p<.001, η²=.055), with adolescents with depression consistently scoring above global mean thresholds across all three time points. Aggression followed a quadratic trajectory (increase from 10.8 to 11.8 years, subsequent decrease at 12.8 years), but remained at elevated baseline levels when depression was present. Although boys and girls showed similar developmental curves (non‑significant interaction), boys displayed greater overall severity (F(1,249)=6.05, p=.015, η²=.024). Depression had a stronger impact in boys (η²=.073) than in girls (η²=.050), with depressed boys exhibiting the highest and most persistent aggression levels.
Conclusions:
Depression acts as a chronic and early‑emerging risk factor for physical–verbal aggression during early adolescence. Although trajectories are similar across sexes, boys show greater severity and reduced decline over time, suggesting increased vulnerability. These findings highlight the need for early screening of depressive symptoms in aggressive youth, and underscore the importance of longitudinal assessment for identifying high‑risk profiles and informing sex‑sensitive preventive interventions.