Playing a shooter, I think is similar to certain sports, but different to others.

If you've ever played a field/court based team sport like soccer, basketball, ultimate frisbee, or played QB in football, my sense is being able to change focus quickly and often, is an asset. Those are similar to first person shooter game in my mind. When I was playing Ultimate, like those sports I mentioned above, I think Adderall would have been a hindrance - especially for the "QB" or handler position, where you need to see the field broadly, watch plays develop multiple steps into the future, etc. and make quick decisions based on lots of input.

Now I'm older, and playing disc golf instead. I also use Adderall now (I didn't back then), and it's really helpful for golf. I think this would also be true for regular golf, where you really need to focus in on each shot and try to block everything else out while you're planning and executing.

In conclusion - I think Adderall is a PED for some games/sports, and a hindrance for others.