This project is a randomized-controlled trial to test the efficacy of computer-based targeted cognitive training (TCT) versus a placebo intervention of commercial computer games in adolescent/young adults at clinical high risk (CHR) for psychosis. TCT is designed to optimize learning-induced neuroplasticity in vulnerable neurocognitive systems. A main aim is to test the hypothesis that this neuroscience-guided TCT intervention will improve neural function, and that these neural improvements will improve cognition and functional outcome. CHR participants will be randomly assigned to 40 hours of TCT or placebo computer games completed within 10 weeks. TCT consists of 20 hours of training in cognition, including processing speed, memory, attention, and cognitive control followed by 20 hours of training in social cognition including affect recognition and theory of mind. Neuroimaging, cognition, social cognition, clinical symptoms, and functional status will be assessed at baseline, after 20 hours/5 weeks of cognitive training (mid-intervention), and after 20 hours/5 weeks of social-cognitive training (post-intervention). Cognition, social cognition, symptoms, and functioning will also be assessed at a 9 month follow-up (i.e. 9 months after intervention completion). We predict that TCT will lead to improvements in neurocognitive function and functional status. The results of this study will provide important information about a benign, non-pharmacological intervention for improving cognition and functional outcome in CHR individuals.