Keep in mind that it is not rare that findings made at the preliminary stage don't hold up when more rigorous studies are undertaken.
There was a total of 81 patients in this trial. What is the statistical significance of the finding?
The exact p-value is in the paper (0.007), or very significant. It's often difficult to get those kind of p-values in real world settings:
http://archpsyc.ama-assn.org/cgi/content/abstract/67/2/146?l...
http://norvig.com/experiment-design.html
Disclaimer: I am already convinced about fish oil (in the first instance for cardiovascular preventive use) and take it daily.
Overwhelming evidence for the benefits of DHA comes from a recent review of some 50 studies, which concluded that higher DHA in babies’ diets translates into better brain function, especially for cognitive and visual function.23 Further evidence that DHA may promote healthy nervous system development comes from a recent study in which researchers divided 53 normal, healthy infants into those exclusively breast-fed and those exclusively bottle-fed with a formula containing no DHA. Using assessments of visual, auditory, and sensory perception, they found definite abnormalities in all three tests in the bottle-fed babies at one year of age.