earlier age of onset for depression relative to non-comorbid depressed individuals, exhibit more depressive symptoms, have higher levels of functional impairment, and more frequently suffer from concurrent anxiety disorders. Importantly, these individuals also present an increased suicide risk (Davis et al., 2006). Given the dramatic economic, social, and health consequences associated with both disorders, the optimization of prevention and treatment efforts is crucial. An understanding of the biological underpinnings of the disorders is essential for such efforts.
