Comorbidity of anxiety and depression in youth: Implications for treatment and prevention.

The high level of concurrent and sequential comorbidity between anxiety and depression in children and adolescents may result from (a) substantial overlap in both the symptoms and items used to assess these putatively different disorders, (b) common etiological factors (e.g., familial risk, negative affectivity, information processing biases, neural substrates) implicated in the development of each condition, and (c) negative sequelae of anxiety conferring increased risk for the development of depression. Basic research on their various common and unique etiological mechanisms has guided the development of efficacious treatments for anxiety and depressive disorders in youth. Potential processes through which the successful treatment of childhood anxiety might prevent subsequent depression are described.