出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2012/08/02 13:39:34」(JST)
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Anxiety (also called angst or worry) is a psychological and physiological state characterized by somatic, emotional, cognitive, and behavioral components.[2] It is the displeasing feeling of fear and concern.[3] The root meaning of the word anxiety is 'to vex or trouble'; in either presence or absence of psychological stress, anxiety can create feelings of fear, worry, uneasiness, and dread.[4] Anxiety is considered to be a normal reaction to a stressor. It may help an individual to deal with a demanding situation by prompting them to cope with it. However, when anxiety becomes overwhelming, it may fall under the classification of an anxiety disorder.[5]
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Anxiety is a generalized mood that can occur without an identifiable triggering stimulus. As such, it is distinguished from fear, which is an appropriate cognitive and emotional response to a perceived threat. Additionally, fear is related to the specific behaviors of escape and avoidance, whereas anxiety is related to situations perceived as uncontrollable or unavoidable.[6] Another view defines anxiety as "a future-oriented mood state in which one is ready or prepared to attempt to cope with upcoming negative events,"[7] suggesting that it is a distinction between future and present dangers which divides anxiety and fear. In a 2011 review of the literature,[8] fear and anxiety were said to be differentiated in four domains: (1) duration of emotional experience, (2) temporal focus, (3) specificity of the threat, and (4) motivated direction. Fear is defined as short lived, present focused, geared towards a specific threat, and facilitating escape from threat; while anxiety is defined as long acting, future focused, broadly focused towards a diffuse threat, and promoting caution while approaching a potential threat. While most everyone has an experience with anxiety at some point in their lives, as it is a common reaction to real or perceived threats of all kinds, most do not develop long-term problems with anxiety. When someone does develop chronic or severe problems with anxiety, such problems are usually classified as being one or more of the specific types of Anxiety Disorders.
Anxiety takes several forms: phobia, social anxiety, obsessive-compulsive, and post-traumatic stress.[9] The physical effects of anxiety may include heart palpitations, tachycardia, muscle weakness and tension, fatigue, nausea, chest pain, shortness of breath, headache, stomach aches, or tension headaches. As the body prepares to deal with a threat, blood pressure, heart rate, perspiration, blood flow to the major muscle groups are increased, while immune and digestive functions are inhibited (the fight or flight response). External signs of anxiety may include pallor, sweating, trembling, and pupillary dilation. Someone who has anxiety might also experience it subjectively as a sense of dread or panic.[citation needed]
Although panic attacks are not experienced by every person who has anxiety, they are a common symptom. Panic attacks usually come without warning and although the fear is generally irrational, the subjective perception of danger is very real. A person experiencing a panic attack will often feel as if he or she is about to die or lose consciousness. Between panic attacks, people with panic disorder tend to suffer from anticipated anxiety- a fear of having a panic attack may lead to the development of phobias.[10] Anxiety is the most common mental illness in America as approximately 40 million adults are affected by it.[9]
The emotional effects of anxiety may include "feelings of apprehension or dread, trouble concentrating, feeling tense or jumpy, anticipating the worst, irritability, restlessness, watching (and waiting) for signs (and occurrences) of danger, and, feeling like your mind's gone blank"[11] as well as "nightmares/bad dreams, obsessions about sensations, deja vu, a trapped in your mind feeling, and feeling like everything is scary."[12]
The cognitive effects of anxiety may include thoughts about suspected dangers, such as fear of dying. "You may... fear that the chest pains are a deadly heart attack or that the shooting pains in your head are the result of a tumor or aneurysm. You feel an intense fear when you think of dying, or you may think of it more often than normal, or can’t get it out of your mind."[13]
The behavioral effects of anxiety may include withdrawal from situations which have provoked anxiety in the past.[14] Anxiety can also be experienced in ways which include changes in sleeping patterns, nervous habits, and increased motor tension like foot tapping.[14]
The symptoms of anxiety include excessive and ongoing worry and tension, an unrealistic view of problems, restlessness or a feeling of being "edgy", irritability, muscle tension, headaches,sweating, difficulty concentrating, nausea, the need to go to the bathroom frequently, tiredness, trouble falling or staying asleep, trembling, and being easily startled.[15]
An evolutionary psychology explanation is that increased anxiety serves the purpose of increased vigilance regarding potential threats in the environment as well as increased tendency to take proactive actions regarding such possible threats. This may cause false positive reactions but an individual suffering from anxiety may also avoid real threats. This may explain why anxious people are less likely to die due to accidents.[16]
The psychologist David H. Barlow of Boston University conducted a study that showed three common characteristics of people suffering from chronic anxiety, which he characterized as "a generalized biological vulnerability," "a generalized psychological vulnerability," and "a specific psychological vulnerability."[17] While chemical issues in the brain that result in anxiety (especially resulting from genetics) are well documented, this study highlights an additional environmental factor that may result from being raised by parents suffering from chronic anxiety.
Research upon adolescents who as infants had been highly apprehensive, vigilant, and fearful finds that their nucleus accumbens is more sensitive than that in other people when deciding to make an action that determined whether they received a reward.[18] This suggests a link between circuits responsible for fear and also reward in anxious people. As researchers note, "a sense of ‘responsibility,’ or self agency, in a context of uncertainty (probabilistic outcomes) drives the neural system underlying appetitive motivation (i.e., nucleus accumbens) more strongly in temperamentally inhibited than noninhibited adolescents."[18]
Neural circuitry involving the amygdala and hippocampus is thought to underlie anxiety.[19] When people are confronted with unpleasant and potentially harmful stimuli such as foul odors or tastes, PET-scans show increased bloodflow in the amygdala.[20][21] In these studies, the participants also reported moderate anxiety. This might indicate that anxiety is a protective mechanism designed to prevent the organism from engaging in potentially harmful behaviors.
Although single genes have little effect on complex traits and interact heavily both between themselves and with the external factors, research is underway to unravel possible molecular mechanisms underlying anxiety and comorbid conditions. One candidate gene with polymorphisms that influence anxiety is PLXNA2.[22]
Anxiety can be a symptom of an underlying health issue such as chronic obstructive pulmonary disease (COPD), heart failure, or heart arrythmia.[23]
Abnormal and pathological anxiety or fear may itself be a medical condition falling under the blanket term "anxiety disorder". Such conditions came under the aegis of psychiatry at the end of the 19th century[24] and current psychiatric diagnostic criteria recognize several specific forms of the disorder. Recent surveys have found that as many as 18% of Americans may be affected by one or more of them.[25]
Standardized screening tools such as Zung Self-Rating Anxiety Scale, Beck Anxiety Inventory, Taylor Manifest Anxiety Scale and HAM-A (Hamilton Anxiety Scale) can be used to detect anxiety symptoms and suggest the need for a formal diagnostic assessment of anxiety disorder.[26] The HAM-A (Hamilton Anxiety Scale) measures the severity of a patient's anxiety, based on 14 parameters, including anxious mood, tension, fears, insomnia, somatic complaints and behavior at the interview.[27]
The philosopher Søren Kierkegaard, in The Concept of Anxiety, described anxiety or dread associated with the "dizziness of freedom" and suggested the possibility for positive resolution of anxiety through the self-conscious exercise of responsibility and choosing. In Art and Artist (1932), the psychologist Otto Rank wrote that the psychological trauma of birth was the pre-eminent human symbol of existential anxiety and encompasses the creative person's simultaneous fear of – and desire for – separation, individuation and differentiation.
The theologian Paul Tillich characterized existential anxiety[28] as "the state in which a being is aware of its possible nonbeing" and he listed three categories for the nonbeing and resulting anxiety: ontic (fate and death), moral (guilt and condemnation), and spiritual (emptiness and meaninglessness). According to Tillich, the last of these three types of existential anxiety, i.e. spiritual anxiety, is predominant in modern times while the others were predominant in earlier periods. Tillich argues that this anxiety can be accepted as part of the human condition or it can be resisted but with negative consequences. In its pathological form, spiritual anxiety may tend to "drive the person toward the creation of certitude in systems of meaning which are supported by tradition and authority" even though such "undoubted certitude is not built on the rock of reality".
According to Viktor Frankl, the author of Man's Search for Meaning, when a person is faced with extreme mortal dangers, the most basic of all human wishes is to find a meaning of life to combat the "trauma of nonbeing" as death is near.
According to Yerkes-Dodson law, an optimal level of arousal is necessary to best complete a task such as an exam, performance, or competitive event. However, when the anxiety or level of arousal exceeds that optimum, the result is a decline in performance.
Test anxiety is the uneasiness, apprehension, or nervousness felt by students who had a fear of failing an exam. Students who have test anxiety may experience any of the following: the association of grades with personal worth; fear of embarrassment by a teacher; fear of alienation from parents or friends; time pressures; or feeling a loss of control. Sweating, dizziness, headaches, racing heartbeats, nausea, fidgeting, and drumming on a desk are all common. Because test anxiety hinges on fear of negative evaluation, debate exists as to whether test anxiety is itself a unique anxiety disorder or whether it is a specific type of social phobia.
While the term "test anxiety" refers specifically to students, many workers share the same experience with regard to their career or profession. The fear of failing at a task and being negatively evaluated for failure can have a similarly negative effect on the adult.
Humans are, naturally, a social species who generally require social acceptance. Therefore, because of the importance of being accepted among society and conforming to its rules and norms, humans dread the disapproval of others. It is this apprehension of being judged by others that is the basic cause of the anxiety one may feel in a social environment.[29]
Anxiety when meeting or interacting with unknown people is a common stage of development in young people. For others, it may persist into adulthood and become social anxiety or social phobia. "Stranger anxiety" in small children is not considered a phobia. In adults, an excessive fear of other people is not a developmentally common stage; it is called social anxiety. According to Cutting,[30] social phobics do not fear the crowd but the fact that they may be judged negatively.
Social anxiety varies in degree and severity. Whilst for some people it is characterized by experiencing discomfort or awkwardness during physical social contact (e.g. embracing, shaking hands, etc.), while in other cases it can lead to a fear of interacting with unfamiliar people altogether. There can be a tendency among those suffering from this condition to restrict their lifestyles to accommodate the anxiety, minimizing social interaction whenever possible. Social anxiety also forms a core aspect of certain personality disorders, including Avoidant Personality Disorder.[citation needed]
Overwhelming anxiety, if not treated early, can consequently become a generalized anxiety disorder (GAD), which can be identified by symptoms of exaggerated and excessive worry, chronic anxiety, and constant, irrational thoughts. The anxious thoughts and feelings felt while suffering from GAD are difficult to control and can cause serious mental anguish that interferes with normal, daily functioning.[31]
The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) includes specific criteria for diagnosing generalized anxiety disorder. The DSM-IV states that a patient must experience chronic anxiety and excessive worry, almost daily, for at least 6 months due to a number of stressors (such as work or school) and experience three or more defined symptoms, including, “restlessness or feeling keyed up or on edge, being easily fatigued, difficulty concentrating or mind going blank, irritability, muscle tension, sleep disturbance (difficulty falling or staying asleep, or restless unsatisfying sleep).”[32]
If symptoms of chronic anxiety are not addressed and treated in adolescence then the risk of developing an anxiety disorder in adulthood increases significantly.[33] “Clinical worry is also associated with risk of comorbidity with other anxiety disorders and depression” which is why immediate treatment is so important.[33]
Generalized anxiety disorder can be treated through specialized therapies aimed at changing thinking patterns and in turn reducing anxiety-producing behaviors. Cognitive behavioral therapy (CBT) and short-term psychodynamic psychotherapy (STPP) can be used to successfully treat GAD with positive effects lasting 12 months after treatment.[34] There are also other treatment plans that should be discussed with a knowledgeable health care practitioner, which can be used in conjunction with behavioral therapy to greatly reduce the disabling symptoms of generalized anxiety disorder.
Anxiety can be either a short term 'state' or a long term "trait." Trait anxiety reflects a stable tendency to respond with state anxiety in the anticipation of threatening situations.[35] It is closely related to the personality trait of neuroticism. Such anxiety may be conscious or unconscious.[36]
Anxiety induced by the need to choose between similar options is increasingly being recognized as a problem for individuals and for organisations:[37][38]
"Today we’re all faced with greater choice, more competition and less time to consider our options or seek out the right advice."[39]
In a decision context, unpredictability or uncertainty may trigger emotional responses in anxious individuals that systematically alter decision-making. [40] There are primarily two forms of this anxiety type. The first form refers to a choice in which there are multiple potential outcomes with known or calculable probabilities. A second form refers to the uncertainty and ambiguity related to a decision context in which there are multiple possible outcomes with unknown probabilities. [40]
Paradoxical anxiety is anxiety arising from use of methods or techniques which are normally used to reduce anxiety. This includes relaxation or meditation techniques[41] as well as use of certain medications.[42] In some Buddhist meditation literature, this effect is described as something which arises naturally and should be turned toward and mindfully explored in order to gain insight into the nature of emotion, and more profoundly, the nature of self.[43]
In Positive psychology, anxiety is described as the mental state that results from a difficult challenge for which the subject has insufficient coping skills.[44]
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| リンク元 | 「concern」「care」「disturbance」「心配」「trouble」 |
| 関連記事 | 「anxious」 |