Dr. Michael Lyon discussed the importance of DHA in eliminating ADD symptoms (see video below)…
What is DHA.
here is a great explanation from wikipedia
Docosahexaenoic acid (commonly known as DHA; 22:6(ω-3), all-cis-docosa-4,7,10,13,16,19-hexa-enoic acid; trivial name cervonic acid) is an omega-3 essential fatty acid. In chemical structure, DHA is a carboxylic acid with a 22-carbon chain and six cis double bonds; the first double bond is located at the third carbon from the omega end.
Fish oils are rich in DHA. Most of the DHA in fish and more complex organisms originates in photosynthetic and heterotrophic microalgae, and becomes increasingly concentrated in organisms as it moves up the food chain. DHA is also commercially manufactured from microalgae; Crypthecodinium cohnii and another of the genus Schizochytrium. Most animals make very little DHA through metabolism; however small amounts are manufactured internally through the consumption of α-linolenic acid, an omega-3 fatty acid found in chia, flax, and many other seeds and nuts.
DHA is metabolized to form the docosanoids—several families of potent hormones. DHA is a major fatty acid in sperm and brain phospholipids, and especially in the retina. Dietary DHA may reduce the risk of heart disease by reducing the level of blood triglycerides in humans. Low levels of DHA result in reduction of brain serotonin levels and have been associated with ADHD, Alzheimer’s disease, and depression, among other diseases, and there is mounting evidence that DHA supplementation may be effective in combating such diseases (see external links at the end of this article).”