Associations between trajectories of depressive symptoms and cognitive performance in Chinese adolescents

Subclinical depressive symptoms and the associated risk of cognitive deficits have been overlooked. We aimed to investigate depressive symptom trajectories and the effect of depressive symptoms on cognitive performance among Chinese adolescents. The research population of our study was 1314 adolescents aged 10-15 years old from the China Family Panel Studies. The Center for Epidemiologic Studies Depression Scale was used to assess the depressive symptoms of adolescents. Vocabulary and mathematics tests were used to test fluid intelligence. Memory and number series tests were used to test crystal intelligence. The 6-year depressive symptom trajectories of adolescents were identified by the latent class mixed model. Linear regression models and Generalized Estimating Equation models were applied to test the associations between depressive symptom trajectories and cognitive performance. We identified three distinct trajectories of depressive symptoms: (a) low depressive symptom trajectory (88.51%), (b) remitting depressive symptom trajectory (5.86%), (c) decreasing depressive symptom trajectory (5.63%). We found that decreasing depressive symptom trajectory predicted worse fluid intelligence (β: -0.51, 95% CI: -0.88, -0.13) and crystal intelligence (β: -2.09, 95% CI: -3.78, -0.41) compared with low depressive symptom trajectory. Gender-stratified analysis showed that the negative association between depressive symptoms trajectory and crystal intelligence was only found in males. Depressive symptom episodes in early adolescence were associated with worse cognitive performance later. Performing mental health screenings, especially during the sensitive windows of cognitive development, is critical to reducing the negative impact of depressive symptoms.