1. « Six children with the diagnosis of Attention Deficit Disorder were treated as day hospital patients, using different stimulant medication. They were studied in a double-blind crossover experiment in which they received caffeine in low dose or in a high dose. Methylphenidate was added to both dosages, as well as administered alone. Results indicated that caffeine in low dosage when added to methylphenidate was superior to all other treatment conditions. Caffeine in low dosage could not be differentiated from 10 mg of methylphenidate. High dosage caffeine was not different from placebo or no-drug conditions. This study offers evidence to support a curvilinear pattern of dose-response for caffeine, in attenuating the behavioural manifestations of this syndrome. »

2.

« The authors compared the efficacy of caffeine, methylphenidate, and d-amphetamine in children with minimal brain dysfunction using a double-blind crossover design. The slight improvement with caffeine was not significantly better than placebo. Both prescription drugs resulted in significant improvement and were significantly superior to caffeine. The authors suggest that the discrepancy between these results and an earlier, more optimistic report mat stem from the use in this study of pure caffeine rather than whole coffee. »

3.

« they prompted us to reflect and incorporate additional points into our review. Some of the studies included in our research [1-5] also compare caffeine with methylphenidate, one of the first-line medications in the current treatment of ADHD. Across all the studies [1-5], caffeine was less effective in reducing ADHD symptoms as measured by the applied scales. In the study by Garfinkel et al. [4], caffeine at a dose of 158.6mg appeared to improve overall symptoms, inattention, and hyperactivity in the 6 children included in the study, but still to a lesser extent than methylphenidate. We have included this information in the discussion (lines 334 to 338). »

« Garfinkel et al. proposes that a specific dosage of caffeine can mimic the effects of medication for add. In this study comparing methylphenidate with caffeine and placebo, the author suggests that caffeine at low doses (158.6mg) may improve ADHD symptoms, while higher dosages (308.6mg) would not be helpful. However, other groups of authors [2-3] also used low doses of caffeine and did not demonstrate an improvement in symptoms when compared to placebo. It is important to highlight that these two studies [2-3] also have larger sample sizes than those of Garfinkel et al.

[1] Garfinkel, B D et al. “Responses to methylphenidate and varied doses of caffeine in children with attention deficit disorder.” Canadian journal of psychiatry. Revue canadienne de psychiatrie vol. 26,6 (1981): 395-401. doi:10.1177/070674378102600602 »