Attention deficit hyperactivity disorder (ADHD) is now one of the most common children’s mental health conditions. It involves symptoms of inattention or impulsivity and hyperactivity that lead to behavioral impairments. Approximately 50 percent of children diagnosed with ADHD continue to show clinically significant symptoms and impairment as adults.

A great deal of research has investigated the possible role of caffeine in ADHD. Caffeine is a psychoactive stimulant drug, which can increase alertness and reduce drowsiness. Coffee, tea, soft drinks and chocolate all contain caffeine and are consumed around the world. Approximately 90 percent of adults in North America consume caffeine daily.

It is widely believed that caffeine boosts attention in normal adults, but research results are unclear. Some studies find better performance on memory tasks; others find that caffeine aids concentration but impairs short-term memory. There is also a general belief that caffeine makes people more anxious and hinders sleep. Caffeine withdrawal may trigger headache, fatigue, irritability and nervousness.

As it is a stimulant, caffeine has been investigated as a potential treatment for attention deficit disorder. Its use as a therapy is not widespread because it was found in research studies to be less efficient than other stimulants. But experts writing in 2008 suggest the doses were too low to have a consistent effect. They say that if caffeine proves useful, it “would represent a qualitative increment over the traditional repeated use of psychostimulants, which can have severe side effects if repeatedly used in children.”

Anecdotal evidence suggests that many individuals are already using caffeine to self-medicate ADHD in themselves or their children. Many sufferers find it has the opposite effect than it does in other people: instead of making them more active and stimulated, it actually has more of a “calm-down” effect, and encourages sleep.

The effectiveness of coffee in calming ADHD children has become a great discussion point on websites and forums. Many adults with ADHD also turn to coffee. In fact, some can’t do without it; caffeine’s stimulating effect helps them focus and stay on task.

A similar outcome has been found in animals. A 2005 study of rats with hyperactivity, impulsivity, poor attention, and deficits in learning and memory found a significant improvement in test results when caffeine was administered to the rats beforehand.

The researchers, from the Federal University of Santa Catarina in Brazil, explain that these rats are “considered to be a suitable genetic model for the study of ADHD, since they display hyperactivity, impulsivity, poorly sustained attention, and deficits in learning and memory processes.”