Concerta is a time-released version of the drug Methylphenidate, which is also known as Ritalin, and is used to treat depression, ADHD, and Narcolepsy. It comes in capsules which contain 18,36, or 54 milligrams of Methylphenidate which is slowly released over a period of 8 to 10 hours. Its main benefit over Ritalin is that it only needs to be taken once a day, but it is more expensive than Ritalin, or its generic equivalent. It also means that once you take it, it will be difficult to get any sleep until it wears off in about 12 hours. This can be a benefit or a curse, depending on your need for sleep. Amphetamines are not a subsitute for proper sleep. Disclaimer: This is not information copied directly from the PDR, so it is possible there may be inaccuracies. I am pretty sure this is accurate, as I have taken Concerta for several years.