Considerable clinical and experimental evidence now supports the idea that deficiencies or imbalances in certain highly unsaturated fatty acids may contribute to a range of common developmental disorders including ADHD, dyslexia, dyspraxia and autistic spectrum disorders (ASD).

Definitive evidence of a causal contribution, however, can only come from intervention studies in the form of randomised, double-blind, placebo-controlled trials. Published studies of this kind are still fairly few in number, and mainly involve the diagnostic categories of ADHD and dyslexia, although other trials involving individuals with dyspraxia or ASD are in progress.

The main findings to date from such studies are reviewed and evaluated here with the primary aim of guiding future research, although given that fatty acid supplementation for these conditions is already being adopted in many quarters, it is hoped that some of the information provided may also help to inform clinical practice.