Methylphenidate (MP), a drug which blocks dopamine reuptake, is most commonly used to treat Attention Deficit Hyperactivity Disorder (ADHD), a disorder associated with a disrupted dopamine system in the brain. Though generally effective at treating common ADHD symptomology (e.g. hyperactivity and impulsivity), MP is less effective at treating working memory deficits, which are also associated with ADHD.