Depression and emotional disorders associated with stress and anxiety are the most common of all psychiatric disorders, accounting for a significant proportion of mental illnesses in highly developed countries. The central point of most modern theories of depression is the view that stress can initiate biological processes that increase the risk of illness. According to these theories, the majority of stressful events in life are among the strongest predictors of impending depression.

It has been shown that abnormalities of the hypothalamic-pituitary-adrenal axis (HPA) play a key role in the development of depressive symptoms, persistence of symptoms, and recurrence of depression. Progressive HPA abnormalities caused by traumatic or chronic stress not only trigger depression and anxiety-related behaviors and emotions, but may also result in prolonged excessive cortisol secretion, which may be responsible for neuronal death and hippocampus atrophy observed in people suffering from depression. The neurotoxic effects of glucocorticoids caused by stress can be explained by the inflammatory and neurodegenerative hypothesis of depression, which postulates that oxidative and nitrosative stress contribute to neurodegenerative processes in depression. Some pieces of evidence have shown that the reduction of nitric oxide levels within the hippocampus can induce anti-depressive-like effects, thus implicating endogenous hippocampal nitric oxide in the neurobiology of stress and depression. It is well known that brain tissue is particularly susceptible to oxidative damage, compared to other organs, due to the relatively high content of iron and peroxide fatty acids, in addition to its limited antioxidative capacity.

This Special Issue will focus on the specific molecular pathways underlying oxidative/nitrosative stress-induced psychiatric disorders as well as potential therapeutic bioactive substances or molecules to attenuate these. We encourage submissions such as pre-clinical and review articles describing the interplay between oxidative or nitrosative stress and mood disorders. Contributions of original research are extremely welcome if they provide new insights to further understand the pathophysiological mechanisms of oxidative/nitrosative damage-induced mood disorders and/or the novel discovery of related diagnostics and therapeutics. Review articles that help better understand the existing knowledge regarding the role of oxidative/nitrosative stress in psychiatric disorders and related therapeutics are also encouraged.

Potential topics include but are not limited to the following:

• Molecular mechanisms of bioactive substances or molecules influencing oxidative/nitrosative stress and inflammation in psychiatric diseases
• New experimental models for the in vitro or in vivo evaluation of oxidative/nitrosative and inflammatory-based pathologies in psychiatric disorders
• Oxidative/nitrosative stress as a therapeutic target to mitigate mood disorders
• Antioxidants in psychiatric disorders
• Effects of bioactive substances or molecules active against mood disorders on reactive oxygen species/reactive nitrogen species in vitro and in vivo assays
• Effects of bioactive substances or molecules on the activity of enzymes involved in the regulation of oxidative/nitrosative stress in mood disorders