Psychiatric disorders and omega-3 fatty acids.

Psychiatric disorders, especially mood disorders in children and adolescent are serious problem of all over the world in the field of child and adolescent psychiatry. In the recent years mood disorders occur in the earlier age. The prevalence of major depression (MD) is about 1-2% in preadolescent children and 3-8% in adolescents. When the major depression is not treated there is a big risk of worsening of symptoms, risk of suicide and development of comorbid disorders. The quality of life of the patient and its family is decreasing in the whole view. The molecular basis of major depression is not well known. The main pathomechanism of MD is in noradrenergic, serotonergic and dopaminergic pathway dysregulation, nutition factors, which can influence structure and metabolism of lipids. It was found decreased level of omega 3 fatty aids (FA), increased ratio of omega 6/omega 3 FA in the serum and in erythrocyte membrane. It is supposed that the oxidative neuronal injury can be prevented by dietary supplementation of antioxidants and that membrane phospholipids can be repaired by dietary supplementation of fatty acids. Omega-3 fatty acids may also participate in modulation of membrane fluidity, which influences the transmission of neurotransmitters. The membrane fluidity is affected by the ratio of phospholipids to free cholesterol. In addition, activation of the inflammatory response was found in depressive patients through increased production of pro-inflammatory cytokines (IL-1b, IL-6, interferon gamma, TNF-alpha) and eicosanoids (prostaglandin E2) in blood and cerebrospinal fluid. This results in increased lipid peroxidation and degradation of polyunsaturated fatty acids, which may result in increased oxidative stress. Omega-3 fatty acids also stimulate anti-inflammatory cytokines (IL-10) or inhibit the cyclooxygenase, platelet aggregation and formation of eicosanoids. The potential molecular mechanisms will be discussed.