I'm quite sensitive to caffeine... I have to be especially careful with it because too much can exacerbate my anxiety.
I think it's absurd that the doctor made such a blanket statement and said it won't keep you up because you have adhd.
Yes, it is true, it may help calm and focus some people with adhd. But there are a lot of factors. I know lots of people who are not kept up by caffeine, and lots of people who are.
It depends so much on the individual, comorbidity, etc. Any doctor who makes a blanket statement like that would make me uncomfortable, personally.