Oxidative stress can be defined as an imbalance between pro-oxidant molecules produced by the body during metabolism and members of the antioxidant system, in favor of the former. Antioxidant defense mechanisms include antioxidant enzyme systems and molecules (vitamins, minerals, etc.) which have the ability to detoxify free oxygen radicals.
The brain is highly vulnerable to oxidative stress since it has limited antioxidant capacity, high energy demand and high lipid content. Moreover, each brain region may have a genetically determined different vulnerability levels to oxidative stress.
Oxidative stress, which is included in the pathogenesis of cancer, aging, cardiovascular and neurodegenerative disorders, is also considered for pathogenetic mechanisms underlying psychiatric disorders including schizophrenia, bipolar disorder, depression, autism and attention deficit hyperactivity disorder. There are accumulating data about increased oxidative stress particularly in childhood autism and therefore antioxidant therapies are considered as an alternative treatment option. In addition, vitamin and mineral supplementation are recommended to compensate low intake when children with autism have feeding problems. The data about the effects of antioxidant therapies in autism are restricted but promising. Since oxidative stress is a common finding in the pathogenesis of different disorders, it can be suggested that individual differences, including single nucleotide polymorphisms of the genes coding for members of the antioxidant defense system, might determine the vulnerability level to oxidative stress. Individual genetic differences might also be the determinant of the level of benefit from antioxidant vitamin therapies. Not only the factors related to the biochemistry of leading antioxidant vitamins (vitamin A, C and E) but also the disease and patient related differences might be acting on the response to supplementation with these vitamins. These two groups of factors might determine the details of supplementation therapies with antioxidant vitamins in the future: 1) Factors related to the patient and the nature of the disease, i.e. the affected brain areas for a specific disorder, the vulnerability of these brain areas to oxidative stress, accompanying diseases and possible effects of antioxidant vitamin supplementation on the pathogenesis of these comorbid diseases; 2) Factors related to the biochemistry of the antioxidant vitamins in the body, i.e., polymorphisms of molecules mediating intestinal absorption and blood-brain transfer of vitamins, important effects of these vitamins on specific gene regulation and effects of vitamins on brain mechanisms.
Antioxidant vitamin supplementation is a promising alternative therapy in psychiatry, but it should be kept in mind that these vitamins might also have undesirable results through their effects on other biological processes. This part of the panel will focus on the study results of antioxidant vitamin supplementation therapies in child psychiatry and molecular data about the genetic and biochemical processes of antioxidant vitamins in the body.