Abnormal Psychology

Anxiety Disorders 269

(e.g., cortisol), which usually accompany the fi ght-or-fl ight response (Otte et al.,

2002). Thus, panic is not the same thing as the ordinary stress response, although

it may arise in part through some mechanisms that are also involved in helping us

respond to emergencies.

Finally, serotonin may also play a role in panic disorder; this idea is supported

by the fact that SSRIs can reduce the frequency and intensity of panic attacks

(DeVane, 1997). Serotonin affects the locus coeruleus in complex ways, and it may

exert its effects on panic attacks indirectly, by altering the operation of this brain

structure (Bell & Nutt, 1998).

Genetics

Genetic factors appear to play a role in the emergence of panic disorder. In fact, fi rst-

degree biological relatives of people with panic disorder are up to eight times more

likely to develop the disorder than are control participants, and up to 20 times

more likely to do so if the relative developed it before 20 years of age (Crowe et al.,

1983; Torgersen, 1983; van den Heuvel et al., 2000). Twin studies have yielded simi-

lar results by examining concordance rates; a concordance rate is the probability that

both twins will have a characteristic or disorder, given that one of them has it. The

concordance rate in pairs of female identical (monzygotic) twins is approximately

24%, in contrast to 11% for pairs of fraternal (dizygotic) twins (Kendler et al.,

1993). However, the genetic predisposition is not specifi c for panic disorder. One

twin study revealed that 20% of the heritability of panic disorder arises from factors

that also lead to GAD and PTSD and another 20% is specifi c to panic disorder; the

remaining 60% of the heritability was accounted for by nonshared environmental

factors, such as particular traumatic experiences (Chantarujikapong et al., 2001).

Earl Campbell wasn’t the only one in his family to experience anxiety: His paternal

aunt, maternal uncle and two of his sisters had signifi cant anxiety symptoms.

Psychological Factors

We saw earlier that not all cases of panic disorder are related to a person’s threshold

for detecting suffocation—some cases of panic disorder arise from learning. Thus,

behavioral and cognitive theories can also help us understand how panic disorder

and agoraphobia arise and are perpetuated: People come to associate certain stimuli

with the sensations of panic, and then develop maladaptive beliefs about those stim-

uli and the sensations that are related to anxiety and panic.

Learning: An Alarm Going Off

Learning theory offers one possible explanation for panic disorder. Initially, a person

may have had a fi rst panic attack in response to a stressful or dangerous life event (a

true alarm). This experience produces conditioning, whereby the initial bodily sen-

sations of panic (such as increased heart rate or sweaty palms) become false alarms

associated with panic attacks. Thus, the individual comes to fear

thoseinteroceptive cues (that is, cues received from the interior of

the body) or the external environment in which they had the panic

attack. As these normal sensations that are part of the fi ght-or-fl ight

response come to be associated with subsequent panic attacks, the

bodily sensations of arousal themselves come to elicitpanic attacks

(learned alarms). The person then develops a fear of fear—a fear that

the arousal symptoms of fear will lead to a panic attack (Goldstein &

Chambless, 1978), much as S did in Case 7.2. Earl Campbell de-

scribed his fear of fear: “Living with the thought that at any moment

you may have to go through another attack is horrible. It creates an

entirely new kind of anxiety” (Campbell & Ruane, 1999, p. 115).

After developing this fear of fear, the person tries to avoid behaviors

or situations where such sensations might occur (Mowrer, 1947;

White & Barlow, 2002).

Concordance rate

The probability that both twins will have a

characteristic or disorder, given that one of

them has it.

People whose hearts sometimes beat too quickly

can be treated with a device implanted under the

skin that shocks the heart, which causes it to beat

at a normal speed again. However, the shocks can

be uncomfortable and alarming. Research suggests

that people who receive more frequent and intense

shocks are more likely to develop panic disorder,

which arises as a conditioned fear in response to

the automatic shocks (Godemann et al., 2001).

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