Stress-related disorders
Stress-related disorders can include mental health disorders that are a result of an atypical response to both short and long-term anxiety due to physical, mental, or emotional stress. These disorders can include, but are not limited to obsessive-compulsive disorder and posttraumatic stress disorder. Stress is a conscious or unconscious psychological feeling or physical condition resulting from physical or mental 'positive or negative pressure' that overwhelms adaptive capacities. It is a psychological process initiated by events that threaten, harm or challenge an organism or that exceed available coping resources and it is characterized by psychological  responses that are directed towards adaptation. Stress is wear and tear on the body in response to stressful agents. Hans Selye called such agents stressors and said they could be physical, physiological, psychological or sociocultural. And stress is not an anxiety disorder and it is not a normative concept. A person typically is stressed when positive or negative (e.g., threatening) experiences temporarily strain or overwhelm adaptive capacities. Stress is highly individualized and depends on variables such as the novelty, rate, intensity, duration, or personal interpretation of the input, and genetic or experiential factors. Both acute and chronic stress can intensify  morbidity from anxiety disorders. One person's fun may be another person's stressor. For an example, panic attacks are more frequent when the predisposed person is exposed to stressors. Stress reduction strategies. Stress-reduction strategies can be helpful to many stressed/anxious people. However, many anxious persons cannot concentrate enough to use such strategies effectively for acute relief. (Most stress-reduction techniques have their greatest utility as elements of a prevention plan that attempts to raise one's threshold to anxiety-provoking experiences.) The five R's of stress and anxiety reduction. Five core concepts are used to  reduce anxiety or stress. Defenses. Defense mechanisms are behavior patterns primarily concerned with protecting ego. Presumably the process is unconscious and the aim is to fool oneself. It is intra psychic processes serving to provide relief from emotional conflict and anxiety. Conscious efforts are frequently made for the same reasons, but true defense mechanisms are unconscious. Some of the common defense mechanisms are: compensation, conversion, denial, displacement, dissociation, idealization, identification, incorporation, introjection, projection, rationalization, reaction formation, regression, sublimation, substitution, symbolization and undoing. Summary. The major function of these psychological defenses is to prevent the experiencing of painful emotions. There are  several major problems with their use. Stress as in clinical medicine. Acute stress disorder. Acute stress disorder occurs in individuals without any other apparent psychiatric disorder, in response to exceptional physical or psychological stress. While severe, such reactions usually subside within hours or days. The stress may be an overwhelming traumatic experience (e.g. accident, battle, physical assault, rape) or unusually sudden change in social circumstances of the individual, such as multiple bereavement. Individual vulnerability and coping capacity play a role in the occurrence and severity of acute stress reactions, as evidenced by the fact that not all people exposed to  exceptional stress develop symptoms. However, an acute stress disorder falls under the class of an anxiety disorder. Symptoms. Symptoms show considerable variation but usually include: An initial state of "DAZE" with some constriction of the field of consciousness and narrowing of attention, inability to comprehend stimuli, disorientation. Followed either by further withdrawal from the surrounding situation to the extent of a dissociative stupor or by agitating and over activity. Autonomic signs of "panic anxiety". The signs are: tachycardia (increased heart rate), sweating, hyperventilation (increased breathing). The symptoms usually appear within minutes of the impact of the stressful stimulus and disappear  within 2–3 days. Post-traumatic stress disorder (PTSD). This arises after response to a stressful event or situation of an exceptionally threatening nature and likely to cause pervasive distress (great pain, anxiety, sorrow, acute physical or mental suffering, affliction, trouble) in almost anyone. Causes. The causes of PTSD are: natural or human disasters, war, serious accident, witness of violent death of others, violent attack, being the victim of sexual abuse, rape, torture, terrorism or hostage taking. The predisposing factors are: personality traits and previous history of psychiatric illness. Typical symptoms. Flashbacks are the repeated reliving of the trauma in the  form of intrusive memories or dreams, intense distress at exposure to events that symbolize or resemble an aspect of the traumatic event, including anniversaries of the trauma, avoidance of activities and situations reminiscent of the trauma, emotional blunting or "numbness", a sense of detachment from other people, autonomic hyperarousal with hypervigilance, an enhanced startle reaction and insomnia, marked anxiety and depression and, occasionally, suicidal ideation. Treatment. Psychiatric consultation: exploration of memories of the traumatic event, relief of associated symptoms and counseling. Prognosis. The course is fluctuating but recovery can be expected in the majority of cases. Few people may show  chronic course over many years and a transition to an enduring personality change In surgery. Stress ulceration. Stress ulceration is a single or multiple fundic mucosal ulcers that causes upper gastrointestinal bleeding, and develops during the severe physiologic stress of serious illness. It can also cause mucosal erosions and superficial hemorrhages in patients who are critically ill, or in those who are under extreme physiologic stress, causing blood loss that can require blood transfusion. Ordinary peptic ulcers are found commonly in the “gastric antrum and the duodenum” whereas stress ulcers are found commonly in “fundic mucosa and can be located  anywhere within the stomach and proximal duodenum”.