Depression and reduced neural response to emotional images: Distinction from anxiety, and importance of symptom dimensions and age of onset

Abnormal patterns of attention to threat and reward have been proposed as potential mechanisms of dysfunction in anxiety and unipolar depressive disorders. However, few studies have simultaneously examined whether these patterns of attention are shared among disorders or distinguish between them. In the present study, we recorded the Late Positive Potential (LPP), an event-related potential and putative index of motivated attention, from 145 patients with anxiety and unipolar depressive disorders and 32 controls, as they viewed blocks of rewarding and threatening images, respectively. We found that a current diagnosis of depression was associated with a reduced LPP to rewarding visual stimuli. This appeared to be specific to a subgroup of individuals with early onset depression; this subgroup was also characterized by a reduced LPP to threatening images. Anxiety diagnosis and age of onset of anxiety, whether comorbid with depression or not, was unrelated to the magnitude of the LPP. Finally, a transdiagnostic symptom dimension measuring current severity of suicidal ideation was related to a reduced LPP to both rewarding and threatening images. These data suggest that dysfunction in neural markers of attention to threat and reward can effectively distinguish features of depression from anxiety, particularly early onset depression, and may track suicidal ideation across disorders.