Milte, Catherine2025-12-172025-12-172011https://hdl.handle.net/1959.8/120031xiv, 241 pages :illustrations (some colour).Includes bibliographic references.This thesis examines the role of polyunsaturated fatty acids (PUFA) in mental health across the lifespan. Attention deficit hyperactivity disorder (ADHD), prevalent in childhood, and the mental disorders of older age: depression and cognitive impairment will be the primary focus. Two interventions were conducted; one with children with ADHD either with or without learning difficulties and one with elderly adults showing symptoms of mild cognitive impairment (MCI). In both studies diets were supplemented with either fish oil, which was rich in the long-chain (LC) omega-3 (n-3) PUFAs eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), or a placebo oil rich in n-6 PUFAs. Relationships between erythrocyte LC n-3 PUFA status and mental health were assessed at baseline, and changes in mental health outcomes were assessed in relation to changes in fatty acid incorporation into erythrocytes as a result of supplementation.enFish oilsFish oilsFish oils in human nutritionOmega-3 fatty acidsthesis