Methylphenidate

Methylphenidate is the most widely prescribed stimulant medication for ADHD worldwide. It is the active ingredient in brand-name products such as Ritalin and Concerta. It works by blocking the reuptake of dopamine and norepinephrine at the synapse, increasing the availability of both in the brain's prefrontal regions.

The therapeutic effect is significant for most people: better concentration, less impulsivity, clearer thinking, and a greater ability to start and finish tasks. Roughly 70% of people with ADHD respond well to methylphenidate.

It is a controlled substance in most countries, requiring a special prescription — the exact scheduling varies by jurisdiction, so it's worth checking local regulations. Used correctly for ADHD, it does not cause dependence. Common side effects include reduced appetite, insomnia if taken too late in the day, and increased blood pressure in some people.