Adderall is most commonly used to treat Attention Deficit Hyperactivity Disorder (ADHD). It is also used to treat narcolepsy, a condition that causes excessive daytime sleepiness. Adderall is considered a first-choice treatment option for ADHD due to its effectiveness in improving attention and focus, while also reducing impulsive behaviors. Both Adderall and Adderall XR (extended-release) have been studied extensively, showing that they can significantly help individuals with ADHD manage symptoms more effectively.