Abstract
There is mounting evidence that functional deficiencies or imbalances in certain highly unsaturated fatty acids (HUFA) of the omega-3 and omega-6 series may contribute to a wide range of developmental and psychiatric conditions, including dyslexia, dyspraxia, attention deficit hyperactivity disorder (ADHD), autism, depression, bipolar disorder and the schizophrenia spectrum. These nutrients are essential to the development and function of the brain, but the omega-3 HUFA in particular (eicosapentaenoic and docosahexaenoic acids) are often lacking from modern diets. The evidence implicating omega-3 fatty acids in these conditions is summarized here, with a focus on the results from randomized controlled treatment trials. These indicate that treatment with eicosapentaenoic acid can reduce symptoms in adults with mood disorders, schizophrenia and possibly Huntington’s disease. In children, preliminary evidence suggests that omega-3 HUFA could also reduce some of the behavioural and learning difficulties associated with ADHD, dyslexia and related conditions. The key features of most of these conditions can be found in milder form as part of normal individual differences in mood, behaviour and cognition. The evidence presented here therefore has implications for the general population, and indicates that an adequate dietary intake of omega-3 fatty acids in particular may be crucial for optimal mental health and functioning.