The purpose of this research study is to see if melatonin improves sleep and the sleep-wake patterns (also known as circadian rhythm) in children, teenagers, and young adults (ages 11-30) with at-risk symptoms. Melatonin is naturally produced in the brain and controls sleep-wake patterns. At-risk symptoms can be feeling like you do not want to do be around other people as much, difficulties with focus, and having beliefs that most people around you don’t have. At-risk symptoms can also be experiences like having jumbled up thoughts, your mind playing tricks on you, or seeing or hearing things that are not there. To see if melatonin changes sleep in youth with at-risk symptoms, we are giving some youth with at-risk symptoms a melatonin pill and some a placebo (a pill without any medication in it) for 6 months.