In psychology, stress is a feeling of strain and pressure. Symptoms may include a sense of being overwhelmed, feelings of anxiety, overall irritability, insecurity, nervousness, social withdrawal, loss of appetite, depression, panic attacks, exhaustion, high or low blood pressure, skin eruptions or rashes, insomnia, lack of sexual desire (sexual dysfunction), migraine, gastrointestinal difficulties (constipation or diarrhea), and for women, menstrual symptoms. It may also cause more serious conditions such as heart problems. Also, experimental research which has been performed on animals, also displayed results relating to stress and negative effects on the body. It has been shown that stress contributes to the initiation and development of specific tumors within the body.
Small amounts of stress may be desired, beneficial, and even healthy. Positive stress helps improve athletic performance. It also plays factor in motivation, adaptation, and reaction to the environment. Excessive amounts of stress however, may lead to many problems in the body that could be harmful. Three diseases that are influenced by stress are clinical depression, cardiovascular disease, and human immunodeficiency virus (HIV).
Stress can be external and related to the environment, but may also be created by internal perceptions that cause an individual to have anxiety or other negative emotions surrounding a situation, such as pressure, discomfort, etc., which they then deem stressful, for example in PTSD.
External factors that by themselves are not threatening or stressful are deemed such for someone experiencing PTSD. Triggers can be stressful, such as when a person reports stress when hearing a song on the radio or seeing a type of object that may remind the person of prior threatening events. Humans experience stress, or perceive things as threatening, when they do not believe that their resources for coping with obstacles (stimuli, people, situations, etc.) are enough for what the circumstances demand. When we think the demands being placed on us exceed our ability to cope, we then perceive stress.
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