Alzheimer's disease is a neurological disease that gradually decreases a person's cognitive functioning. As the disease progresses, it becomes difficult for people to answer basic questions or recognize loved ones. Alzheimer's is the most common cause of senile dementia and is most common found in elderly people. Due to being the common cause of senile dementia, Alzheimer's becomes a topic in most Psychology books and courses. The cause of the disease is not understood and is very complex. One possible cause of the disease is being under chronic stress. Most psychology textbooks discuss a link between stress and a variety of physical and mental issues.