Panic disorder

In a typical scenario, a thirtysomething year old woman presents with a racing heart, chest pain, shortness of breath, sweating, and a feeling of impending doom. She thinks to herself, “Am I having a heart attack?” or “Am I going to die”? She is rushed to the emergency department, but various investigations show nothing abnormal, and she is later referred to a psychiatrist.

Why has a referral to a psychiatrist been made when the patient has serious physical symptoms, such as palpitations, chest pain, or hyperventilation? This is panic disorder, in which the body and mind interact to produce very unpleasant experiences but which respond to treatment in at least 35% of cases.^w1

Panic attacks are “sudden sometimes unexpected bursts of extreme anxiety, mostly manifesting as severe physical symptoms: cardiovascular, respiratory, gastrointestinal, neurological, and autonomic.” Panic disorder, on the other hand, means recurrent attacks of panic in a period of at least one month. Symptoms might include palpitations, hyperventilation, chest tightness, sweating, numbness, paraesthesia, depersonalisation, trembling, nausea, feeling of choking, dizziness, fear of losing control or going mad, and fear of dying. These symptoms are not the result of a general medical condition, such as hyperthyroidism or phaeochromocytoma, or of another psychiatric disorder, such as depression, or substance misuse. The different components of a panic attack are given in table 1 with some examples.

Table 1: Components of panic disorder

The lifetime prevalence of panic disorder is estimated to be 4.7%.^w1 Twice as many women are affected as men. The onset of panic disorder is more often seen in late adolescence and in the mid-30s. It can be disabling when associated with agoraphobia—that is, fear of open spaces or public places—which may severely affect social and personal life. Panic disorder may also be associated with other psychiatric conditions, such as generalised anxiety disorder, major depressive disorder, or substance abuse. A high risk of suicidal ideation and suicide attempts is also seen in patients with panic disorder, particularly when associated with depression.

How panic disorder arises

Biological theories

Several theories have been postulated to explain the cause of panic disorder. The biological approach hypothesises the involvement of various neurotransmitters, including serotonin, noradrenaline, and γ aminobutyric acid, particularly in the amygdala, a brain region known to regulate fear, emotion, and anxiety.

Another hypothesis is that a neuroanatomical “fear network”^w2 that involves the amygdala is overactivated and produces excessive physiological and behavioural symptoms when exposed to benign stimului.

Psychological theories

Clark proposed that panic attacks occur because of the catastrophic interpretation of certain bodily sensations.^w3 Anyone may experience physical sensations when he or she feels anxious. For example, thoughts and images of being in the supermarket may be perceived as a source of threat, resulting in apprehensive feelings and physical sensations. People vulnerable to panic disorder may perceive these physical symptoms as more serious than they really are. This is often described as a “catastrophic misinterpretation.”

For example, palpitations may be misinterpreted as evidence of an impending serious heart attack. A slight breathing difficulty may be misperceived as impending serious respiratory failure and consequent death. A shaky feeling may be misinterpreted as losing control of oneself or going mad (table 2). This increases apprehension, which further increases physical symptoms and so on, leading to a vicious cycle that results in a panic attack (fig ¹).

Table 2: Common misinterpretations of physiological symptoms

Fig 1 A vicious cycle in a panic attack: the cognitive approach (Adapted from Clark’s cognitive model of panic attack^w3)

A person with a panic attack may get small changes in heart rate or respiratory rate, but it is the faulty perception of these changes that leads to seeking emergency help. In some cases, a diagnosis of a panic attack is made only after tests have failed to find a cardiorespiratory cause.

Cognitive behaviour therapy

Cognitive behaviour therapy combines both cognitive and behavioural theories to describe and treat a psychological illness. Cognitive theory holds that our cognitions such as thinking, memory, perception, and learning, as linked to the self, world, and others, are basic to the way we feel and behave. Behavioural theory says that our behaviours are the products of conditioning through rewards or punishments. Thoughts, behaviours, feelings, and physical symptoms are interlinked and influence each other. A useful model that is often used to describe this interaction is the hot cross bun model (fig ²).

Fig 2 Hot cross bun model of interaction between thoughts, behaviours, feelings, and physical symptoms^w4

Cognitive behaviour therapy is not about problem solving but recognising distorted thinking and unhelpful behaviours. These are identified, evaluated, and modified through cognitive and behavioural tasks, and the evidence for and against is established. Patients are helped to develop insight into their rational and irrational thinking that might be contributing to their problems. Cognitive behaviour therapy is in fact a collaborative and “here and now” type of psychotherapy. Sessions tend to take place every week for about 12-16 weeks.

In panic disorder, patients display three types of behaviour that maintain the illness—avoiding situations that are thought might precipitate panic attacks; escaping from situations in which a panic attack occurs; and safety seeking during panic attacks. The person starts to think that these behaviours have prevented the catastrophic outcomes of having such attacks, and this belief reinforces these behaviours. The therapy is intended to break this link between thought, feelings, physiological symptoms, and behaviour. Patients are helped to understand this link and how it maintains the disorder. They are also helped to identify and test evidence and explanations for their misinterpretation of physical symptoms.^w2 Behavioural interventions include breathing retraining exercises, relaxation techniques, and inhalation of carbon dioxide.

Cognitive behaviour therapy has been shown to be effective in treating and maintaining long term remission in panic disorder.^w5 In addition, it is an effective treatment for many other psychiatric disorders, including generalised anxiety, obsessive-compulsive, and post-traumatic stress disorders as well as bulimia and depression,^w5 but the demand for cognitive behaviour therapy often outweighs the supply.

Other approaches in the management of panic disorder are also used, including antidepressants such as selective serotonin reuptake inhibitors. In addition, benzodiazepines, such as diazepam, help to reduce the symptoms of anxiety in the acute setting. Social circumstances, such as stress at work, poor relationships, and financial problems are also known to contribute to psychiatric morbidity, and improving these circumstances in the management of panic disorder may be further explored (table 3).

Table 3: Management of panic disorder

Understanding the link between the mind and the body is important in panic disorder. A holistic approach to managing any illness should include a model of illness that integrates the body with the mind. Panic disorder is a good example of the importance of this fascinating link.

Competing interests: None declared.

Provenance and peer review: Not commissioned; externally peer reviewed.

References w1-w5 are on student.bmj.com.

1. w1 Roy-Byrne PP, Craske MG, Stein MB. Panic disorder. Lancet 2006; 368 (9540): 1023-32.
2. w2 Gorman JM, Kent JM, Sullivan GM, Coplan JD. Neuroanatomical hypothesis of panic disorder, revised. Am J Psychiatry 2000; 157 (4): 493-505.
3. w3 Clark DM. A cognitive approach to panic. Behav Res Ther 1986; 24 (4): 461-70.
4. w4 Salkovskis PM, Clark DM, Hackmann A. Treatment of panic attacks using cognitive therapy without exposure or breathing retraining. Behav Res Ther 1991; 29 (2): 161-6.
5. w5 Butler AC, Chapman JE, Forman EM, Beck AT. The empirical status of cognitive-behavioural therapy: a review of meta-analyses. Clin Psychol Rev 2006; 26 (1): 17-31.

       

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