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Is Anxiety Psychological or Physical?

What is anxiety, where does it come from, and when is it a problem?

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Anxiety can be defined as ‘a state consisting of psychological and physical symptoms brought about by a sense of apprehension at a perceived threat’. Fear is similar to anxiety, except that with fear the threat is, or is perceived to be, more concrete, present, or imminent.


The psychological and physical symptoms of anxiety vary according to the nature and magnitude of the perceived threat, and from one person to another. Psychological symptoms may include feelings of fear and dread, an exaggerated startle reflex, poor concentration, irritability, and insomnia.

In mild to moderate anxiety, a surge in the hormone adrenaline (epinephrine) gives rise to physical symptoms such as tremor, perspiration, and muscle tension.

In severe anxiety, hyperventilation (over-breathing) can lead to a fall in the concentration of carbon dioxide in the blood. This gives rise to an additional set of physical symptoms, among which chest discomfort, numbness or tingling in the hands and feet, dizziness, and faintness.


Fear and anxiety can be a normal response to life experiences, a protective mechanism that has evolved both to prevent us from entering into potentially dangerous situations and to assist us in escaping from them should they befall us regardless. For instance, anxiety can prevent us from coming into close contact with disease-carrying or poisonous animals such as rats, snakes, and spiders; from engaging with a much stronger or angrier enemy; and even from declaring our undying love to someone who is unlikely to spare our feelings.

If we do find ourselves in a potentially dangerous situation, the fight-or-flight response triggered by fear can help us to mount an appropriate response by priming our body for action and increasing our performance and stamina.

In short, the purpose of fear and anxiety is to preserve us from harm, and, above all, from death—whether it be literal or metaphorical, biological or psychosocial.


Although some degree of anxiety can improve our performance on a range of tasks, severe or inappropriate anxiety can have the opposite effect and hinder our performance. Thus, whereas a confident actor may perform optimally in front of a live audience, a novice may suffer from stage fright and freeze.

From a medical standpoint, anxiety becomes problematic when it becomes so severe, frequent, or longstanding as to prevent us from fulfilling our occupational or social obligations. This often owes to a primary anxiety disorder, although in some instances the anxiety is secondary to another mental disorder such as depression or schizophrenia, or to a medical disorder such as hyperthyroidism (overactive thyroid gland) or alcohol withdrawal.


Primary anxiety disorders are very common, affecting almost one in every five people in the US in any given year. As broadly conceived, they present in a great variety of forms, including phobic anxiety disorders, panic disorder, generalized anxiety disorder, and post-traumatic stress disorder. With the exceptions of social phobia and obsessive-compulsive disorder (which is sometimes classed as an anxiety disorder), women are more likely to be affected than men. Anxiety disorders often co-present with depression or depressive symptoms, other anxiety disorders, personality disorder, or alcohol or drug misuse.


As discussed, inappropriate anxiety may overlie an anxiety disorder or a broad range of mental and medical disorders. Mental disorders associated with anxiety include mood disorders such as depression, psychotic disorders such as schizophrenia, and eating disorders such as anorexia or bulimia. Physical disorders associated with anxiety include endocrine disorders such as hyperthyroidism, Cushing’s disease, phaeochromocytoma, and hypoglycaemia, and drug and alcohol intoxication or withdrawal.

Genetic, environmental, and psychological factors can all predispose or contribute to an anxiety disorder. A genetic predisposition to anxiety disorders may manifest as 'neurotic' personality traits. The core feature of neurosis is anxiety, but neurosis can also manifest as a range of other problems such as irritability, depression, perfectionism, and obsessive-compulsive tendencies.

In terms of environmental factors, an anxiety disorder may be triggered or perpetuated by stress and stressful events, especially those involving a threat. They may also result from traumatic events in childhood such as parental neglect or physical abuse.

In many cases, psychological factors, often superimposed upon genetic and environmental factors, play an important role. According to cognitive behavioural theories, anxiety disorders result from inappropriate thought processes and belief systems. According to psychoanalytic theory, anxiety disorders have their origins in childhood events such as separation or loss, and in unresolved childhood conflicts of psychosexual development.


Ultimately, it is difficult to separate the psychological from the physical, since the psychological, which arises in the brain, is also in some sense physical, and has manifold physical effects and vice versa. However, anxiety disorders that are secondary to another mental or medical disorder are usually best treated by treating the primary, or underlying, cause.

For further advice on anxiety management, see my related article, Coping with Anxiety.

Neel Burton is author of Heaven and Hell: The Psychology of the Emotions and other books.

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