A Cochrane review looked at whether polyunsaturated fatty acid supplements, often called PUFAs, help children and teens with ADHD. It combined 37 trials, with 30 used in the pooled analysis. Together these trials included more than 2374 children and adolescents aged 6 to 18 who had been diagnosed with ADHD. The trials ran in many countries, and supplements were given for two weeks up to six months.
The strongest evidence showed no benefit. Parents rated their child's overall ADHD symptoms no differently whether the child took a supplement or a placebo, and the researchers were highly confident in this result. The same held for inattention and for hyperactivity and impulsiveness. There was weaker, low-certainty evidence that supplements might help on a simple improved-or-not measure in the medium term.
Supplements looked about as safe as placebo, with no clear difference in side effects or in how many people dropped out. The authors noted weaknesses: small studies, differing entry rules, different types and doses of supplement, and short follow-up.
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The numbers Stats and what the terms mean
The statistics behind the plain-language claims above.
- Gillies, 2023: parent-rated overall ADHD symptoms, supplement compared with placebo, medium term, SMD -0.08 (95% CI -0.24 to 0.07; 16 studies, 1166 participants). The review rated this high-certainty evidence of no effect, and the range includes 0, so the data fit no difference too.
- Gillies, 2023: improved or not, supplement compared with placebo, medium term, RR 1.95 (95% CI 1.47 to 2.60; 3 studies, 191 participants). The review rated this low-certainty evidence that supplements may improve symptoms.
What the terms mean:
- d (Cohen's d): how big a difference is, between groups or from before to after, on a shared scale. Roughly, 0.2 is small, 0.5 is moderate and 0.8 is large. A minus sign only shows which way the difference went; the finding says which side it favors.
- SMD (standardized mean difference): the same idea as d, often used when a review pools several studies. Read it on the same scale.
- RR (risk ratio, or relative risk): how many times as often something happened in one group as in another. 1 means no difference.
- 95% CI (confidence interval): the range of values that fit the data reasonably well. A narrow range means a more precise result. If the range includes "no difference" (0 for d, g, SMD, MD, r or β; 1 for OR, AOR, RR or HR), the data fit no difference too. The true value isn't certain to be inside it.
Source: Gillies D, Leach M, Perez Algorta G. Polyunsaturated fatty acids (PUFA) for attention deficit hyperactivity disorder (ADHD) in children and adolescents. Cochrane Database of Systematic Reviews (2023). doi:10.1002/14651858.CD007986.pub3