Autoimmune diseases are usually multifactorial that include things like genetics, environmental factors, diet, hormones, and stress. We know that genetics can be a huge factor, but not the deciding factor that causes someone to develop an autoimmune disease. For example, Crohns disease is multifactorial and someone who has a parent that has Crohn's disease is 20-30% more likely to develop it (Feuerstein, 2017). Many of these diseases are out of our control, but these multifactorial ones can be managed with good diet, behaviors, and treatment. In the main research article I was looking at, it emphasized that both physiological and physical stress have been implicated in the development of autoimmune diseases. They saw this effect in animal and human studies. They also found that up to 80% of patients reported emotional stress before disease onset (Stojanovich, 2008). The stress before and the onset of the diseases then increases the stress of the person which creates this vicious cycle where the person is in a prolonged period of stress that disrupts the immune system. This is also due to stress triggered hormones being released that leads to immune dysregulation and increasing cytokine production. The specific cytokine talked about was IL-6 which is a proinflammatory cytokine. Anytime we have chronic inflammation, it's typically a bad thing that leads to something like arthritis depending on the area being affected.
To sum it up, stress is a factor to autoimmune disease and is one of the factors that we can limit. Habits and lifestyle choice are some of the best ways to have a better life despite having an autoimmune disease.
Feuerstein, J. D., & Cheifetz, A. S. (2017). Crohn
Disease: Epidemiology, Diagnosis, and Management. Mayo Clinic
proceedings, 92(7), 1088–1103. https://doi.org/10.1016/j.mayocp.2017.04.010