Stress and the immune system

The modulation of the immune system by the nervous system is a complex, bidirectional network. The dysregulation of the immune function by stress is done through the modified secretion of various hormones (adrenaline, glucocorticoids, growth hormone, prolactin, etc.) that are important modulators of it. Glucocorticoids, for example, are well known for their anti-inflammatory and immune suppressants effects but continuous, long-lasting secretion can lead to increased inflammation and decreased sensitivity of immune cells to glucocorticoids effects.

Even if a short, acute stress has been suggested to enhance the immune system, and thus be beneficial, it may also trigger allergic manifestations, such as asthma, eczema or urticaria. Migraine headache can also result from an acute stress-related impact on the immune system.

When stress becomes chronic, research in the last decades have shown that it affects the immune system function in many ways:

  • Studies suggest that stressed people have delayed, weaker and/or short-lived immune response to vaccines

  • Stress can dysregulate the immune response to pathogens and increase the risk of developing infectious disease, as well as enhancing its severity

  • It also affects wound healing, by disrupting the production of critical proteins (cytokines), thus delaying the healing process

  • Chronic stress might also be linked to premature ageing of immune cells, leading to an increased risk in developing age-related disease (osteoporosis, arthritis, frailty and functional decline)

  • Immune dysfunction and chronic inflammation induced by chronic stress increase the risk of cancer and auto-immune diseases

  • Psychological stressors have also been shown to be able to reactivate latent herpes viruses

In addition, stressed people show tendency to have health habits that put them a greater risk: reduced and poorer sleep, less exercising, malnutrition, greater propension to abuse of alcohol, cigarettes and other drugs.

As the interactions between the immune and nervous systems are complex, research continues to better understand them and find new approaches for treatment.