Materiales y métodos 1. Modelo de simulación

The nature of panic and its incidence are described in this chapter.

The main explanations are set out and evaluated, and the methods of treatment are described.

A panic is an episode of intense fear of sudden onset. The fear, often bordering on terror, is accompanied by disturbing bodily sensations, dif®culty in reasoning, and a feeling of imminent cata-strophe. There is a close relationship between panic and anxiety, and at times they feed each other. Hence, episodes of panic provide a useful basis for analysing the relationship between fear and anxiety.

Elevated anxiety increases the probable occurrence of an episode of panic (Margraf, Ehlers, & Roth, 1986) and, in turn, a panic is usually followed by prolonged anxiety, a residue of anxiety. In addi-tion to this short-term residue of anxiety, Klein, Zitrin and Woerner (1977, p. 27) observed that ``as a result of these panics, they [patients]

develop [longer-term] anticipatory anxiety''.

In all of the various forms of anxiety disorder, including obsessional-compulsive disorders (OCDs), social phobias, and so on, episodes of panic are common. According to Barlow and Craske (1988), ``panic is an ubiquitous problem among patients with anxiety disorders and at least 83% of patients in any diagnostic category reported at least one panic attack,'' (p. 20). (The term ``panic episode'' is preferable to the more usual ``panic attack'', which has misleading connotations, especially with heart attacks. However, the terms used by the original writers are retained throughout this text.) The term

``panic'' is derived from the Greek god Pan, whose shrill and unexpected noises frightened people.

The feelings of imminent catastrophe are described in various ways. Some people report feeling that ``something terrible is hap-pening to me'', ``I feel that I am in great danger'', or ``I feel that I am about to completely lose control''. During a panic, people commonly fear that they might be dying, losing control, going insane, or losing consciousness. Some of the panics are unexpected and seem to ``come

out of the blue''. However, the majority are provoked by exposure to identi®able stressors and can therefore be anticipated (McNally, 1994). Most people experience an occasional episode of panic in which the cause of the fear is evident. The threat of a serious motor accident can provoke it, as can an attack by a vicious dog. These predictable panics are also distressing and share some features of the unexpected panics, but they are easily understandable. By contrast, episodes of panic that occur unexpectedly can be bewildering and therefore especially troubling. A panic that occurs when at leisure in one's home is dif®cult to comprehend. In the absence of any apparent psychological stress, it is not surprising that affected people grope for a medical cause of their distress. The panics that occur ``out of the blue''Ðunpredictably and inexplicablyÐare a central feature of panic disorder. On average, episodes of panic last between 5 and 20 minutes, are distressing, and leave the person feeling drained and anxious.

Panics that occur in response to a true threat are appropriate, if at times excessive, and they serve to protect the person from pain, injury, or discomfort. In contrast to these true alarms, episodes of panic that arise in response to threats that are minimal, or entirely misconceived, can be regarded as similar to the triggering of a false alarm. In fact, two of the leading theorists on the subject of panic disorder, Barlow (1988, 2002) and Klein (1987, 1993) construe abnor-mal episodes of panic as essentially false alarms, although their explanations of the nature and causes of these false alarms differ.

The following are some examples of unexpected panics triggered by unusual and even threatening events that were then catastrophi-cally misinterpreted and resulted in the rapid onset of intense fear, i.e. panic:

A 23-year-old woman described her ®rst unexpected episode of panic in these words: ``I was at home one week-end and suddenly had trouble with my breathing. My heart was pounding and I began sweating heavily. I thought that my heart had given in and felt that I was about to die. My husband rushed me to the hospital emergency where they tested my heart and assured me that there was no danger. I gradually calmed down and returned home after an hour or so, feeling shaken but no longer terri®ed''.

A physically ®t 32-year-old security guard experienced his

®rst panic while exercising in the gym. During the course

of his customary programme of exercises he suddenly became extremely sensitive to his rapid heart beats and interpreted them as a sign that he was about to have a heart attack. He became understandably frightened and, gasping for air, asked a friend to call for an ambulance. He was rushed to the emergency room of the local hospital but during the trip felt that he might die before reaching help. At the hospital he was treated as an emergency and immediately wheeled into the examination room. No evidence of any cardiac irregularity or other problem was found and he was assured that he was healthy and could return home. After resting at the hospital for an hour, during which he felt relieved but exhausted, he returned home. Two weeks later he had another unexpected panic while jogging and again the doctor at the hospital reassured him about his health. A full examination carried out by his family doctor the following day led to the diagnosis of panic disorder and he was referred for psychological treatment.

In these two examples, unusual/unexplained bodily sensations were catastrophically misinterpreted as signs of an imminent heart attackÐa rather typical sequence of events in the onset of panic.

Other common catastrophic thoughts involved in episodes of panic are the feeling that one is losing control, the fear of going insane, the fear of losing consciousness, and the fear of acting strangely and/or screaming.

A 25-year-old lawyer was walking across a bridge one afternoon when she began to feel extremely dizzy and her heart began to pound. She felt that she might lose con-sciousness, or worse, lose self-control and run into the road in the face of oncoming traf®c. These thoughts terri®ed her and she ¯ed as fast as she could off the bridge.

Thereafter she had a number of repetitions of the episode of panic and in each case the major fear was that she would lose control or act in a bizarre manner or self-destructively. These thoughts in turn led to a further fear that she might go insane and end up in a restrictive ward at a psychiatric hospital.

An anxious young accountant had a long history of worries about her health. On one occasion, she nearly choked when

a piece of meat was lodged in her throat. She thought that she was about to choke to death and was terri®ed. Even after the meat was dislodged, she remained frightened and upset for more than an hour. After this incident she became extremely fearful of choking and limited herself to a very narrow, strict diet of soft and easily swallowed foods. Even so, she occasionally felt that some food had not gone down smoothly and would then feel panicky. Episodes were always provoked by the same, easily recognized event and she was able to predict which foods and situations would provoke a panic, and hence avoided them.

In the DSM classi®cation of disorders, the de®ning features of a panic disorder are that the person has repeatedly experienced episodes of panic, some of which were unexpected, and at least one of the episodes was followed by persistent worries (lasting one month or more) of having another panic. During the episodes, at least four of the following sensations/feelings are experienced: shortness of breath, dizziness or faintness, increased heart rate, trembling or shaking, choking, sweating, stomach distress or nausea, feeling that one's surroundings or self are not quite real, feelings of numbness, hot ¯ashes or chills, chest pain or discomfort, a fear of dying or losing control or going crazy. In cases of panic disorder, the episodes might occur daily or several times a week. Typically, after the ®rst episode of unexpected and inexplicable panic, medical reassurance is suf®-cient to provide temporary relief and a state of calm. However, when the second or subsequent episodes occur, conventional reassurance is of limited value. The person begins to fear that more episodes will take place, and at unpredictable times and in any setting. He or she becomes anxious and apprehensive, develops a pattern of avoidance, and rarely achieves a satisfactory sense of safety.

In a majority of cases, the occurrence of repeated panics is followed by restrictions of mobility. People tend to avoid situations in which they feel that a panic may occur and/or situations from which a rapid escape might be dif®cult. They plan in advance a particular route, time of the journey, and escape exits. Places and activities that are commonly avoided include supermarkets, theatres, cinemas, public transport, driving unaccompanied, bridges, and tunnels. Being caught in a traf®c jam or standing in a long queue are common causes of anxiety. In many instances, the affected person becomes fearful of being alone at home and needs the reassuring presence of a trusted person who can provide safety or take actions to provide safety (e.g.

calling a doctor or ambulance) if a catastrophe threatens. If these fears and the consequent avoidance of ``unsafe'' places becomes excessive, the diagnosis of panic disorder is expanded to panic disorder with agoraphobia.