It is a well-known fact that anxiety has become one of the most serious mental health issues in many countries across the world. It can affect people of all regions, societies, countries or continents. Without a second thought, anxiety can affect not only the way you think and feel, but also the way you live your life. According to the World Health Organization, the overall number of people who suffer from anxiety disorders is estimated to 450 million people. One individual in four will confront one or more kind of anxiety disorders during the lifetime, while anxiety exists constantly in a long-term period in about 10% of the adult population in a global level (World Health Organization, 2004).
In addition, according to The Economic Burden of Anxiety Disorders, a study which was conducted by the ADAA and published in the Journal of Clinical Psychiatry, anxiety has costed in the U.S. more than $42 billion in a year, almost one third of the $148 billion total mental health bill for the U.S. More than $22.84 billion of those costs are associated with the repeated use of mental healthcare services, due to the fact that people with anxiety disorders seek relief from their symptoms. Also, individuals with any kind of anxiety disorder have three to five times more likelihood to visit a doctor and six times more possibility to be hospitalized for psychiatric disorders than individuals who do not confront anxiety disorders (anxiety statistics, 2015). But what exactly can be conceptualized as anxiety?
Anxiety can be characterized as an emotion, with an unpleasant state of internal turmoil and low sense of control, which is often accompanied by different kinds of behavior, such as pacing back and forth, rumination and complaints in the body (Seligman et al, 2000). Also, anxiety can be described as a subjectively unpleasant feeling of dread for many imminent events (Davison, 1968) and as a feeling of worry or fear and uneasiness, which is frequently unfocused and generalized as an overreaction to an event that is being considered subjectively as menacing. In addition, many other symptoms that accompany anxiety can be heart palpitations, difficulty in breathing or hyperventilating, insomnia, dry mouth, a sense of impending doom, excessive sweating etc. (Bouras & Holt, 2007).
Anxiety can be accompanied not only by physical symptoms such as muscular tension, restlessness, fatigue and pain in many parts of the body, but also with crucial mental difficulties, such as low levels of concentration, attention and cognitive performance (Katz et al, 1993). It can be associated with bodily and neurological agitation, distressed body language, facial expressions and decreased levels of social skills and interactions in both sexes (Katz et al, 1993). On the other hand, it is true that anxiety can be appropriate only if it is experienced as regularly, warns us in different situations, where we need to take action and perhaps protect our self and provokes motivations without the existence of unpleasant feelings (American Psychiatric Association, 2013).
As far as the effects of anxiety are concerned, they can be concluded actually in three main domains; cognitive, emotional and behavioral. The cognitive effects of anxiety can include thoughts about imminent but subjectively danger, such as fear of dying or losing the mind. For instance, someone is feared that the chest pains mean heart attack (Kazdin, 2000). Anxiety has been associated with the deterioration of thought process and the inability to make decisions on a rational basis for the everyday life. Also, individuals who have high levels of anxiety, when they asked to reproduce certain sentences or patterns which were shown few minutes before, they could not do it, indicating that also memory can be affected by anxiety (Ansari et al, 2008). The emotional effects of anxiety can be summarized by feelings of apprehension or dread, chronic worry for no specific reasons, anticipating for bad events, feelings of tense or jumpy, watching (and waiting) for signs of danger, irritability, and, a feeling that the mind is gone blank. It can be added as well as nightmares, obsessions in daily life even the phenomenon of Deja vu (Kazdin, 2000). The behavioral effects of anxiety include withdrawal and avoidance from situations or changes in the everyday activities which have provoked anxiety in the past. Anxiety can also provoke changes in sleeping patterns (Barker, 2009).
Anxiety as an emotion is not a current feeling in human life. It exists since mankind appeared in life and through centuries the treatment of anxiety was encountered by many different ways, such as magical spells and herbs. Only the last centuries the use of drugs and psychotherapy appeared to be used as an effective and more appropriate treatment. To be more specific, after the end of 17th century many efforts have been made in order to study anxiety and its causes (Bachrach & Kroll, 1982). In the field of psychology, many directions were shown up and tried to give their answers about anxiety. According to psychodynamic theory, anxiety is the outcome of opposing unconscious desires or fears due to problems with early objects (mother or any other caretaker during childhood) that manifest via different kind of maladaptive defense mechanisms that all individuals have, such as suppression, somatization etc. (Calvin, 1999). On the other hand, according to cognitive theory, cognitive distortions such as overgeneralization, arbitrary inference, negative automatic thoughts activate pathological anxiety (Burns, 1989). As reported by behaviorism, anxiety is learned through classical conditioning (in which a neutral stimulus acquires meaning through association with a crucial stimulus) and maintained through operant conditioning (in which avoidance from the negative experience of anxiety plays eventually a key role in its increase) (Mowrer, 1947).
Moreover, the new field of neurobiology contributed to the deeper understanding of anxiety but in a more biological aspect. It has been proved that brain chemistry and brain function or dysfunctions respectively can alter thoughts, emotions and behaviors. So, when an individual perceives an information or stimulus from the environment as threatening, the levels of many neurotransmitters, such as serotonin, norepinephrine and GABA, alter provoking an imbalance into the brain (Mah et al, 2016). Consequently, that leads to an overreaction of the ventral neural system (amygdala), whereas the dorsal neural system (hippocampus and PFC) is hypoactive. When amygdala is being triggered, it reacts by preparing the body for the ‘’fight or flight’’ response. The last outcome has been proved for many anxiety disorders, such as panic disorders, generalized anxiety disorder (GAD), specific phobias and posttraumatic stress disorder (PTSD) (Mah et al, 2016).
Cognitive Interference Theory (CIT, Sarason et al, 1990) has been used to explain the link between anxiety and low levels of cognitive performance. In this theory, cognitive interference refers to negative off-task self-dialogue that interferes with performance by distracting a person from the task at hand. CIT is in accordance with the Beck’s Theory and his cognitive view about anxiety (Beck et al, 1985), in which the main psychological issue of anxiety is not only a vulnerability arising from an individual’s tendency to devalue his or her problem-solving skills, but also an exaggeration to the degree of threat in the situations. Many studies have supported the CIT by demonstrating lower levels of cognitive performance among people who reported high evaluation anxiety and frequent negative off-task self-dialogue relative to individuals who reported low evaluation anxiety and fewer off-task thoughts (Hammermaster, 1989). Many advocates of CIT postulate that the negative statements interfere with the working memory system, by diverting subject’s attention from on task- processing, resulting a decline in cognitive performance (Coy et al, 2011).
Albeit Cognitive Interference Theory (CIT) received empirical support, it failed to define how anxiety can affect cognitive performance (Eysenck, 2010). The following theory, which is called Processing Efficiency Theory (Eysenck & Calvo, 1992) continued to study anxiety and cognitive performance. It assumed that anxiety provokes detrimental outcomes for the central executive system, in which are included the inhibition, the shifting and the updating functions, but may does not affect in the same way the two other systems, which are the phonological loop and the visuospatial sketchpad. Also, the theory states that the performance effectiveness (the quality of performance) is retained, but the performance efficiency (the relationship between the effectiveness of performance and the amount of effort used to attain that level of performance) is impaired in high trait-anxious individuals. This happening due to the fact that worrisome thoughts interfere with the task at hand, they drain the attentional system and this lead to fewer resources available which impair processing efficiency. (Eysenck & Calvo, 1992). In addition, according to Eysenck (Eysenck & Calvo, 1992) the worrisome thoughts are responsible for the adverse effects of anxiety on cognitive performance.
Attentional Control Theory (ACT) was developed in order to clearly identify which specific executive functions are most affected by anxiety and also explain the mechanism that anxiety affects cognitive performance by introducing attentional control, due to the fact that neither CIT nor processing efficiency theory achieved to profoundly clarify it (Eysenck et al., 2007). So, ACT states that the inhibition and the shifting functions are most impaired and that anxiety affects more the performance efficiency than the performance effectiveness, because of the detrimental effects of anxiety on the attentional control of the inhibition and shifting functions (Eysenck et al., 2007).
Finally, the Attentional Control Theory states that the environmental information can be processed with the aid of two different attentional systems that individuals have. The goal directed (top-down) system is influenced by individuals’ current goals, expectations and knowledge and keeps attention to the task, while the stimulus-driven (bottom-up) attentional system is influenced by salient stimuli (Corbetta & Shulman, 2002). Many studies indicate that in individuals with high levels of anxiety the balance between these two systems can be affected and consequently altered (Corbetta & Shulman, 2002; Bishop et al, 2004). So, there is an increase in the function of the ‘’bottom-up stimulus-driven system’’, while there is a decrease in the use of the ‘’top-down goal-driven system’’, or stated in other words, attention is distracted by threatening stimuli and individuals with high levels of anxiety have not enough resources for the task at hand. Taking everything into consideration, it can be stated that anxiety does influence and impair the overall function and capacity of attentional system (Corbetta & Shulman, 2002).
Nowadays, anxiety has already been distinguished and investigated in two different ways. State anxiety can be characterized as a temporary emotional state, while trait anxiety as a consistent personality attribute (Endler & Kocovski, 2001). State anxiety is mainly being influenced by environmental factors for both sexes whereas trait anxiety is being connected more with genetic effects (Lau et al, 2006).
State anxiety can be described as the presence of unpleasant feelings, such as apprehension and tension which are confronted under specific situations, demands and tasks. State anxiety refers to a temporary condition in response to some perceived and subjective threat, in which the autonomic nervous system is being activated (Eysenck, 1992). Also, it has been associated with a selective processing of emotional and threatening events (Mathews & Macleod, 1994) and with an interpretation of vague events as being dangerous (Eysenck, 1992). According to Eysenck (Eysenck, 1992), state anxiety is determined by trait anxiety and situational stress. Individuals who have high levels of state anxiety during a specific situation or task has been found that they have lower levels of self-efficacy, which influences behavior and decision making and consequently leads to a procrastination of the task or even to the failure (Bandura, 1997). Many studies have shown that attentional system of people with state anxiety is sensitive to and biased in favor of a threat-related- stimuli from the environment and these individuals are prone to focus on their attention toward threat-related-stimuli quite early in the stages of processing, while later, they tend to direct their attention in things which are located away from the potential threat. Consequently, allocation, or otherwise avoidance of threatening stimuli, helps to reduce the levels of state anxiety in a short-term period (Williams et al., 1997).
Test anxiety, referring to the specific form of anxiety about performance with evaluative characteristics, consists of two main elements, worry and emotionality. Worry is being expressed by upsetting concerns, worrisome thoughts and generally by any negative cognitive expression in relationship with the imminent evaluation (Liebert & Morris, 1967). On the other hand, emotionality refers to the perceptions of autonomic arousal because of the evaluative stress (Liebert & Morris, 1967). Worry has been already associated with a strong inverse relationship with performance (Eunsook, 1999) and with many kind of anxiety disorders, such as GAD (Borkovec et al., 1991).
Moreover, working memory is dramatically influenced by high levels of anxiety and instead of focusing on the task, the individuals focus on processes like worrying and ruminating (Eysenck, 1992). One of the most crucial example can be given by the domain of mathematical problem solving. Individuals with high levels of test anxiety for math computations or tasks show a reduction of working memory capacity (Beilock & Carr, 2005; Ashcraft & Kirk, 2001). State anxiety levels are higher when individuals try to complete or solve cognitive tasks in high stake situations, such as job competence, academic performance or any other kind of evaluation indicating that state anxiety interfere with cognitive performance and provokes difficulties in the whole procedure (Coy et al, 2011). Besides, evaluation anxiety has been proved that leads to an increase of state anxiety and cortisol levels, psychophysiological activation, heart rate activity and negative off-task self-dialogue. (Coy et al, 2011).
On the other hand, trait anxiety, albeit it starts in response to a perceived threat, exactly as state anxiety, it differs in its intensity, duration and the range of situations in which it happens. Trait anxiety can be referred to the differences among people in terms of their predisposition to experience state anxiety in response to the anticipation of a threat (Endler & Kocovski, 2001). Also, it has been found that high trait anxious individuals have more intense degrees of state anxiety in specific occasions than most people do, while they experience anxiety toward a broader range of situations or objects than most people. Consequently, trait anxiety can be thought more as a personality characteristic rather than a temporary feeling (Endler & Kocovski, 2001).
In addition, many studies have concluded that individuals with trait anxiety show lower levels of attention on a task while focusing on threatening locations and show a difficulty from shifting to irrelevant threatening stimuli to relevant information or stimuli. However, trait anxious individuals do not only attend to threatening locations but also to locations of safety that can help them to cope with threat (Derryberry & Reed, 1997).
Trait Anxiety has been found that can negatively affect the central executive processing system, which includes functions such as planning, selection, attention and also the phonological loop, which stores and processes auditory information, and the visuospatial sketchpad, which stores and processes visual information (Eysenck, 1992). Also, it has been found that effects on reading performance (reading span task) (Sorg & Whitney, 1992), and has been associated with enhanced attentional capture by an irrelevant singleton during task performance, an interpretation which is in accordance with many state-of-the art EEG studies for the brain function (Moser et al, 2012). According to Eysenck (Eysenck & Eysenck, 1980), trait anxiety can moderate the levels of state anxiety, which are caused by different and innumerable situational demands. Many studies have found an adverse outcome between trait-anxious subjects and cognitive performance during an anticipatory anxiety task (e.g Barrett & Armony, 2006; Deffenbacher & Hazaleus, 1985).
It has been found that there are subtle differences in the way that anxious people process the environmental information and/or stimuli from people who are not anxious. More precisely, three different cognitive biases are linked with high levels of trait anxiety. Memory bias, interpretive bias and attentional bias. Memory biases are investigated by using lists which include neutral and threatening words in order to be learned and recalled. Memory bias exists when more threatening than neutral words are recalled. People with high levels of trait anxiety and also people with depression show memory bias toward negative words (Craik & Lockhart, 1972). Interpretive bias is the tendency of subjects with trait anxiety to interpret vague information in a threatening way. According to Eysenck (Eysenck et al., 1989), high trait- anxious subjects have more possibilities to perceive and process some specific auditory homophones in accordance with their threatening meaning than subjects with no trait anxiety (e.g. die-dye). Also, interpretive bias can be allocated by using text comprehension tasks (MacLeod & Cohen, 1993). The selective attentional bias is the tendency of anxious people to pay more attention to threatening stimuli than people with non-anxiety. The attention of anxious people has been found that is occupied by task irrelevant threatening information (Ouimet et al, 2009).
Taking everything into consideration, it goes without saying that anxiety plays an important role and can negatively control many aspects of our life with innumerable detrimental outcomes. This is why many studies have been conducted until now, so as to examine the crucial relationship between anxiety and cognitive performance (e.g. Eysenck & Calvo, 1992; Beilock & Carr, 2005; Ashcraft & Kirk, 2001) and how can this relationship affect us. Consequently, it has been found that anxiety does impair performance, and especially when the task is complex and the subject must pay high levels of attention and concentration (Eysenck & Calvo, 1992). Many researchers have concluded that anxiety is inversely associated with cognitive performance on tasks such as analogies (Deffeacher, 1977), verbal memory (Mueller, 1977), problem solving (Geen, 1985) and math tasks (Beilock & Carr, 2005). The majority of the studies supports this generalization for both trait and state anxiety (Derakshan & Eysenck, 2009).