Behavioral and Psychosocial Determinants of Gender Differences in Adolescent Mental Health: A Population-Based Cross-Sectional Study in Northern Italy

Background: Gender differences in adolescent mental health are well documented; however, the extent to which modifiable behavioral and psychosocial factors account for the excess of mental health problems in females remains insufficiently quantified. Methods: Data from the 2025 Corona and Psyche South Tyrol (COP-S) survey comprised a base sample of 2,428 adolescents aged 11–19 years (51.4% males) with valid self-reported data. Multivariable regression analyses were conducted on 1,448–1,603 adolescents (depending on the outcome) who provided complete responses to the relevant predictor and outcome measures. Gender differences in depression scores (PHQ-2), anxiety scores (SCARED-GAD), and emotional/behavioral difficulties (SDQ) were examined using Mann-Whitney U and chi-square tests. Multivariable linear regression models were used to assess the associations between mental health outcomes and the ten predictors. Gender effects were quantified by comparing standardized regression coefficients from unadjusted and adjusted models. Results: Female adolescents reported higher anxiety (median 6 vs. 4; rank-biserial r = 0.24), depression (r = 0.13), and emotional/behavioral (r = 0.08) scores than male adolescents. School stress, problematic Internet use, and poor sleep quality were the strongest predictors of all three outcomes (all p < 0.001). After multivariable adjustment, gender remained a significant predictor of anxiety (β = 0.18) and depressive scores (β = 0.09) but no longer reached significance for emotional/behavioral scores (β = 0.04, p = 0.078). The attenuation of the gender effect ranged from 25.3% for anxiety to 37.1% for depression and 58.5% for emotional/behavioral difficulties. Conclusions: Gender differences in adolescent mental health are partially explained by modifiable behavioral and psychosocial factors, with the excess of females in emotional/behavioral scores fully accounted for by these covariates. Persistent gender disparities in anxiety indicate the need for anxiety-specific preventive strategies that target mechanisms beyond the measured behavioral correlates.