"Hyperfocus" comes from the theory that ADHD is not a lack of attention but rather a difficulty focusing one's attention. The idea goes that ADHD people can some times "hyperfocus" on things for very long periods of time.
It should be noted that the idea of hyperfocus isn't actually present in the DSM-5 (the standard classification of mental disorders) and largely came from a smaller group of psychiatrists and authors in recent years. Despite being a very popular concept on the internet (merely posting this comment is going to make me a lightning rod, I know), it's rather contentious concept in official diagnostic circles. It's also extremely misunderstood in internet discussions about ADHD with many non-ADHD people misinterpreting it as a sign that they might have ADHD.
Note that stimulant medication (a common treatment for ADHD) can often make hyperfocus worse, and hyperfocus is a well-known side effect of stimulant medication being dosed too high. It's also not considered unique to ADHD and is definitely not diagnostic for having ADHD. Specifically, focusing for things for long periods of time by itself is definitely not a sign of ADHD.
I'd add that ADHD hyperfocus is focusing on one thing but that the thing is not necessarily what you want it to be. For example, I've become obssessed for a few weeks on boardgames, to the exclusion of everything else but after that I had no interest whatsoever. Sometimes, it can be useful when I'm focusing on something actually relevant to my career, life. Sometimes, like with boardgames, it can lead to me buying 80 board games, and wasting my time on something completely useless...
As regarding to medication, I seldom use my ADHD medication (concerta makes me way too sleepy if I'm sleep deprived and I have a toddler so I'm always mildly sleep deprived) but when I did, it actually stopped the hyperfocus in that it allowed me to think of something else besides my obsession du jour.
i don't know if this counts as hyperfocus, so i'll just call it focus
i can focus on something only when i can detach from everything else. that can be difficult to achieve. because it means that i can forget to take a lunch break, miss meetings, or skip other responsibilities. so most often i am afraid to focus because of all these sideeffects.
that means in order for me to be able focus on something someone has to take care of everything else that requires planning or thinking ahead. sometimes that is not possible. forget focus if i had a fight with my wife and have to worry about what happens when i get home.
on the other hand focus can also be used to avoid some other unpleasant task. the only way to solve that was to find ways to make that task less unpleasant.
It should be noted that the idea of hyperfocus isn't actually present in the DSM-5 (the standard classification of mental disorders) and largely came from a smaller group of psychiatrists and authors in recent years. Despite being a very popular concept on the internet (merely posting this comment is going to make me a lightning rod, I know), it's rather contentious concept in official diagnostic circles. It's also extremely misunderstood in internet discussions about ADHD with many non-ADHD people misinterpreting it as a sign that they might have ADHD.
Note that stimulant medication (a common treatment for ADHD) can often make hyperfocus worse, and hyperfocus is a well-known side effect of stimulant medication being dosed too high. It's also not considered unique to ADHD and is definitely not diagnostic for having ADHD. Specifically, focusing for things for long periods of time by itself is definitely not a sign of ADHD.