**5. The role of psychological association with GI tract autoimmunity**

Stress occurs when a demand of the environment exceeds an individual's ability to adapt [204]. Described by Selye in 1936, stress is defined as an organism attempting to maintain homoeostasis that faces either an actual threat (physical) or a perceived threat (psychological) for which it must adapt its behavior to survive [205]. Stress is not necessarily a negative effect as sometimes it can be a positive aspect for people to motivate them and enhance their performance in life in general and in this case, it's


### **Table 1.**

*Summary of the 5 GI autoimmune diseases.*

called eustress [206]. Trauma and significant life stressors, such as a loss of a loved one or a natural disaster, occur to almost all people at some point in their lives [207]. A decrease in an individual's ability to adapt to environmental factors can lead to events that are negative and cause distress [208]. There are different kinds of stressors that can cause a disturbance: acute (lasting for minutes), brief (for a short duration), or chronic (lasting for a long time) [209]. As a result of their exposure to these stresses, a considerable number of people will develop serious psychiatric reactions, including posttraumatic stress disorder (PTSD). In addition, the acute stress reaction may be best defined as a reaction triggered by a life event that causes great stress or a change in life that triggers an acute stress reaction. Hence, it is apparent that stress and psychiatric disorder can cause physiologic changes. It is possible that the hypothalamic-pituitary-adrenal axis and the autonomic nervous system are disrupted, impairing immune function, and making people more susceptible to physical diseases. Many autoimmune diseases have unknown etiology. It has been speculated that there is a huge influence on the psychiatric reactions to life stressors and their influence in relation to autoimmune diseases. Many animal studies have suggested a close link between them [210]. Nevertheless, human studies are limited [211, 212].
