ADHD and first-episode schizophrenia show distinct scanpaths to emotional faces

Background: Attention deficit hyperactivity disorder (ADHD) and early-onset schizophrenia are both marked by significant deficits in social and emotional functioning. In this study, we tracked visual scanpaths while participants passively viewed emotional faces to examine the processing of facial emotions in patients with ADHD and first-episode schizophrenia (FES). Methods: A corneal reflection technique was used to record eye fixations and saccades in 42 ADHD, 20 FES and 37 matched healthy control participants, between 12 and 18 years of age. Visual scanpaths were recorded while participants viewed happy and sad facial expressions, as well as neutral and nonface control stimuli. Results: FES participants, compared with both ADHD and control participants, were distinguished by ‘restricted’ scanpaths (eg reduced duration and number of fixations and reduced dispersal of fixations), as well as reduced attention to the salient features of positive and negative facial expressions. Conversely, ADHD participants exhibited more dispersed fixations compared with controls, although differences were only significant for the neutral face. Conclusions: Our results suggest that FES and ADHD may be distinguished by at least partially separable deficits in facial emotion processing. While the abnormal scanpaths of FES may reflect an inability to form an integrated gestalt of salient facial features, ADHD might, to some extent, be characterized by an inability to disengage from nonfeature (task irrelevant) facial areas.