The dopamine reuptake inhibitor, Ritalin® (methylphenidate) has been used for almost 50 years to treat children with attention-deficit hyperactivity disorder (ADHD) and, more recently – and controversially, has been used by students to enhance academic performance and as a recreational drug. Although Ritalin® has been prescribed for millions of children, the mechanisms by which it modifies behavioural performance remain poorly understood. Researchers at the University of California, San Francisco have now shown, in animals at least, that Ritalin® improves ability to focus on tasks and directly enhances speed of learning by distinct dopamine receptor-mediated mechanisms.
By co-administering Ritalin® with either the dopamine D1 receptor antagonist, SCH-23390, or the dopamine D2 receptor antagonist, raclopride, the team were able to show the well-known benefit of improved focus was mediated through D2 receptor-dependent mechanisms whereas learning efficiency was enhanced through D1 receptor-dependent mechanisms. The study also established that Ritalin® strengthens synapses and enhances neuroplasticity. A better understanding of the way that Ritalin® improves focus and enhances learning could lead to the development of more targeted drugs for ADHD and learning enhancement.
The study is published in Nature Neuroscience.