What is depression?

Depression is a common and serious mental health condition characterized by persistent feelings of sadness, hopelessness, and a loss of interest or pleasure in activities that were once enjoyable. It can affect how you feel, think, and handle daily activities, and it can interfere with your ability to function normally.


Depression can be triggered by a combination of genetic, biological, environmental, and psychological factors. It can occur at any age, but it often first appears during adolescence or young adulthood. Certain risk factors, such as a family history of depression, traumatic life events, chronic illness, or substance abuse, can increase the likelihood of developing depression.


What is the relationship between depression and oxidative stress?

The relationship between depression and oxidative stress is complex and bidirectional. Oxidative stress occurs when there’s an imbalance between the production of reactive oxygen species (ROS) and the body’s ability to neutralize them with antioxidants. Several factors suggest a potential link between depression and oxidative stress:


  • Inflammation: Depression is associated with increased inflammation in the body, as evidenced by elevated levels of pro-inflammatory cytokines and markers of inflammation in individuals with depression. Inflammatory processes are closely linked to oxidative stress, as activated immune cells produce ROS as part of their defense mechanisms. Chronic inflammation associated with depression can lead to sustained oxidative stress and cellular damage in the brain and other organs.


  • Neurotransmitter Dysfunction: Imbalances in neurotransmitters such as serotonin, dopamine, and norepinephrine are implicated in the pathophysiology of depression. Oxidative stress can impair the function of neurotransmitter systems in the brain by damaging neuronal cells and disrupting signaling pathways. Conversely, alterations in neurotransmitter function can also contribute to oxidative stress by affecting cellular metabolism and energy production.


  • Mitochondrial Dysfunction: Mitochondria are the primary source of ROS production in cells and play a crucial role in cellular energy metabolism. Dysfunction of mitochondria, such as impaired electron transport chain function or reduced antioxidant defenses, can lead to increased ROS generation and oxidative stress. Depression is associated with mitochondrial dysfunction in the brain and peripheral tissues, which may contribute to the development and progression of depressive symptoms.


  • Stress Response: Chronic stress is a major risk factor for depression and is associated with dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, which controls the body’s stress response. Prolonged activation of the HPA axis can lead to increased production of cortisol and other stress hormones, which can induce oxidative stress and damage cellular structures in the brain and other organs.


  • Antioxidant Defenses: Depression is associated with decreased levels of antioxidants in the body, such as vitamins C and E, glutathione, and superoxide dismutase. Antioxidants help neutralize ROS and protect cells from oxidative damage. Decreased antioxidant defenses in individuals with depression may exacerbate oxidative stress and contribute to the pathophysiology of the disorder.


Overall, oxidative stress is thought to play a significant role in the development and progression of depression by contributing to neuronal damage, inflammation, neurotransmitter dysfunction, and mitochondrial impairment.