It is true that the right amount of caffeine can improve concentration, but it can exacerbate hyperactivity and anxiety in those with ADHD.
There’s no blanket rule for adults with ADHD consuming caffeine. If you have ADHD you don’t have to deprive yourself of your caffeine intake completely, but do practise moderation: 500 to 600 mg of caffeine consumption a day is considered too much. Increased heartbeat, shakes and tremors are some of the symptoms those with ADHD may experience with even a low caffeine intake.
Also, bear in mind that if you are on ADHD medication and drink coffee or tea, for example, the stimulant effect will be more pronounced. If you have ADHD limit yourself to the smallest amount of caffeine in the morning – sometimes even one cup of coffee (100 to 200 mg) is too much. Avoid caffeine intake during the afternoon and evening and be aware of how caffeine affects you: Everyone metabolises caffeine differently, with some being more susceptible than others, so it’s really about monitoring yourself and being self-aware.