system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does Adderall (and other similar substances) make one focus so effectively?

When one takes adderall, they are able to focus quite intently on what they are doing - sometimes for hours on end. How does a substance allow one to do that, especially if they have such easily-distracted tendencies?
gpt
Adderall and similar drugs belong to a class of drugs known as **amphetamines**. You may have heard this name as part of the slightly less beneficial **meth**amphetamine. Yes, crystal meth is chemically very similar to Adderall. The more you know.

Amphetamine is a stimulant. Stimulants range from caffeine to nicotine to methamphetamine, and they all work in slightly different ways. Your neurons talk to one another with chemicals, called neurotransmitters. To put it very, very, simply, your neurons need these chemicals so that they can talk to one another. When they are finished talking, they need a bit of a break to recover so they can fire again. This break usually runs about one millisecond, during which these neurons recoup some ions so they can accept transmissions again. What amphetamines do is trigger these cells to release some stored neurotransmitters (the talking chemicals) into the space surrounding them. The upshot of all this is that there's more neurotransmitters available to all the nearby cells, so if they want to talk a bit more frequently, they can run a bit faster (since they don't have to wait to re-synthesize the neurotransmitter themselves). 

So now we know how an amphetamine works. Why, then, does Adderall help focus more so than caffeine, which is also a stimulant? Drugs like caffeine are *global* stimulants. This means that globally, throughout the brain, caffeine encourages increased neurotransmission. (Caffeine works through a different pathway than amphetamine, but it's roughly the same effect). The answer is that while caffeine is a global stimulant, Adderall as a stimulant seems to only stimulate the parts of the brain that do thinking. Scientists don't know why yet, but they know it does. And isn't that good enough for a drug?

I hope this helped.