This narrative review looked back at studies of caffeine in ADHD. It reports no new data and does not say how studies were chosen. Most of the clinical studies came from the 1970s and 1980s and were small studies of hyperactive children.
In children, caffeine was reported to work better than placebo but worse than methylphenidate and d-amphetamine. Low to moderate doses did better than placebo or no treatment. In one study, all 11 hyperactive children improved on caffeine or methylphenidate, with no clear difference between the two. A meta-analysis of 19 small studies, averaging 14.4 people each, analyzed only a subgroup. It found caffeine less effective than stimulants on thinking, movement and mood. The authors state the best dose could be around 150 mg a day, and that caffeine has a half-life of 2.5 to 4.5 hours. The best timing and dose interval are not well understood.
Teens with ADHD were twice as likely to consume caffeine as teens without it. There were no clinical data on caffeine as a treatment in teens or adults, so no conclusions can be drawn for them. Rat studies suggested caffeine helps thinking, though the authors urge caution about animal results.
The authors argue caffeine may have been dropped as a treatment for the wrong reasons. They suggest clinicians might need to consider that cross-tolerance effects from habitual caffeine use, especially heavy use, may negatively affect the clinical management of ADHD in patients receiving stimulants.
Talk to a clinician about your own situation.
The numbers Stats and what the terms mean
The statistics behind the plain-language claims above.
- Walker et al., 2010: how much more likely teens with ADHD were to consume caffeine than teens without ADHD, OR 2.08; 95% CI 1.23 to 3.50, p=0.006. What the terms mean:
- OR (odds ratio) compares the odds of something in one group with another; 2.08 means about twice the odds.
- 95% CI is the range the true value most likely falls in.
- p is the chance of seeing a result this strong if there were no real link; a small value means the result is unlikely to be down to chance.
Source: Ioannidis K, Chamberlain S, Müller U. Ostracising caffeine from the pharmacological arsenal for attention-deficit hyperactivity disorder – was this a correct decision? A literature review. Journal of Psychopharmacology (2014). doi:10.1177/0269881114541014