Effect of depressive symptoms on the evolution of neuropsychological functions over the course of adolescence.

INTRODUCTION: Comprehensive understanding of the association between depression and neuropsychological functioning over the course of adolescence requires developmentally sensitive assessment through longitudinal data. The aim of current study is to examine the concurrent and subsequent effects of depressive symptoms on the initial level and evolution of four neuropsychological functioning domains (i.e., spatial working memory, delayed recall memory, perceptual reasoning, and inhibitory control).

METHOD: Depressive symptoms and neuropsychological functioning were assessed over the course of four years in a sample of 3826 Canadian adolescents. A series of multilevel models estimated the between-person, within-person, and lagged within-person effects of depressive symptoms on each domain of neuropsychological functioning.

RESULTS: Findings suggest that current year and past year depressive symptoms were associated with poorer performance in delayed recall memory and perceptual reasoning tasks. Likewise, past year depressive symptoms were associated with poorer spatial working memory performance. These detrimental effects were stronger in early adolescence.

LIMITATIONS: The current study examined the presence of sub-clinical depressive symptoms but not clinical depression. Moreover, although depressive symptoms and neuropsychological functions were assessed using widely used, valid, and reliable computer-based instruments, the results may not match the accuracy of clinician-based assessments.

CONCLUSIONS: Our results underline the necessity of early intervention for young adolescents to decrease the harms associated with depression. The effect of early-onset depression on the underlying neural substrates of neuropsychological functioning merits further investigation.