Abstract
Neurodivergent youth often experience anxiety and depressive symptoms that may hamper adaptive functioning and well-being. There is little knowledge of how anxiety and depression are related in neurodivergent youth. Therefore, we aimed to examine whether the relationship between anxiety and depressive symptoms is uni- or bidirectional in neurodiverse youth. We assessed self-reported anxiety and depressive symptoms over time in 173 youth (M(baseline age) = 11.7 years, SD = 2.1, 64% males, 36% females). The sample comprised 38 autistic youth, 85 youth diagnosed with attention-deficit/hyperactivity disorder (ADHD), and 50 comparison youth assessed at baseline (T1), 2-year follow-up (T2, 97% retention), and 10-year follow-up (T3, 73% retention). We used cross-lagged models to analyze the data. In neurodivergent youth, more anxiety symptoms at T1 and T2 predicted more depressive symptoms at T2 and T3. Preceding anxiety symptoms were linked with later depressive symptoms, even after accounting for autoregressive effects of depressive symptoms. The results are consistent with a prodromal model in which anxiety symptoms can independently foreshadow the emergence of depressive symptoms over the course of development among neurodivergent youth. Potentially, addressing anxiety symptoms among youth with autism or ADHD could play a role in preventing the onset of youth depression.