The goal of this observational case-control study is to learn how stressful experiences, dietary habits, and blood nutrient levels are associated with gastrointestinal symptoms and symptoms of depression and anxiety in adults aged 18 to 65 years. The study will also examine whether positive psychological resources, such as hope, optimism, resilience, and self-confidence, are related to these associations.
The main questions this study aims to answer are:
* Are stressful experiences in childhood and recent stressful life events associated with gastrointestinal symptoms and symptoms of depression and anxiety?
* Are dietary habits and blood levels of selected nutrients associated with gastrointestinal and psychological symptoms?
* Do psychological resources, such as hope, optimism, resilience, and self-confidence, influence the relationships among stress, nutrition, gastrointestinal symptoms, and psychological well-being?
Researchers will compare 100 participants with gastrointestinal disorders and psychological symptoms or a history of stress with 100 control participants who do not have chronic gastrointestinal symptoms and have low levels of depression and anxiety symptoms.
Participants will:
* Complete questionnaires about stressful experiences, dietary habits, gastrointestinal symptoms, depression and anxiety symptoms, psychological resources, and quality of life.
* Have gastrointestinal sounds recorded.
* Allow blood remaining from routine clinical testing performed before endoscopy to be used to measure cholesterol, vitamin B6, and vitamin C levels. No additional blood draw will be required for this study.
All study assessments will be completed once at enrollment. There will be no follow-up visits, and participants will not receive or be assigned to any treatment as part of this study.