People with schizophrenia and people with attention deficit hyperactivity disorder (ADHD) typically have impairments of attention and emotion perception with poor social functioning; and ADHD like behaviours sometimes appear before the first overt schizophrenia symptoms. So there seem to be similarities between ADHD and presymptomatic schizophrenia. The work reported in this book investigates disorder-specific emotion perception impairments in people with ADHD or first-episode schizophrenia (FES) by using eye movement recordings to map scanpaths of where they look when viewing emotionally expressive faces. The FES group showed ?restricted? scanpaths with a hypervigilance to facial features (eyes, nose, and mouth) suggesting an impaired ability to form an integrated face gestalt. ADHD individuals showed more scattered fixations without any bias to or away from features suggesting an impulsive, inattentive scanning style. These results indicate that poor emotion perception in ADHD is caused by different perceptual impairments than those which cause poor emotion perception in FES. This finding has important implications for developing treatment interventions for these disorders.