A few cups of coffee throughout the day can make a real difference. Some studies have found that caffeine can boost concentration for people with ADHD. Since it’s a stimulant drug, it mimics some of the effects of stronger stimulants used to treat ADHD, such as amphetamine medications.However, caffeine alone is less effective than prescription medications.educed Blood Flow to the Brain. Caffeine is also a vasoconstrictor. That means it makes blood vessels smaller and reduces blood flow. This reduced blood flow is why caffeine helps headaches. Amphetamine medications used to treat ADHD also make blood vessels smaller.