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Chapter 11Psychopathology: Phobic disorders

Division A OverviewClassification and diagnosis of phobic disorders 190

Division B Explanations of phobic disordersBiological explanations of phobic disorders 192Psychological explanations of phobic disorders 194

Division C Therapies for phobic disordersBiological therapies for phobic disorders 196Psychological therapies for phobic disorders 198

End-of-chapter reviewChapter summary 200Exam question with student answer 202

Phobic disordersOverview • Clinical characteristics of the phobic disorders.

• Issues surrounding the classification and diagnosis of phobic disorders, including reliability and validity.

Explanations • Biological explanations of phobic disorders, for example, genetics, biochemistry.

• Psychological explanations of phobic disorders, for example, behavioural, cognitive, psychodynamic and socio-cultural.

Therapy • Biological therapies for phobic disorders, including their evaluation in terms of appropriateness and effectiveness.

• Psychological therapies for phobic disorders, for example, behavioural, psychodynamic and cognitive-behavioural, including their evaluation in terms of appropriateness and effectiveness.

SPecification

Psychopathology Candidates will be expected to study one of the following disorders: • schizophrenia • depression • anxiety disorders – phobic disorders • anxiety disorders – obsessive-compulsive disorder

claSSification and diagnoSiS of Phobic diSorderS

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iSSueS of reliability and validityreliabilityReliability refers to the consistency of a measuring instrument such as a scale to assess fear ratings. Reliability can be measured in terms of whether two independent assessors give similar scores (inter-rater reliability), or whether the test is likely to produce the same results on two separate occasions (test-retest reliability).

Research evidence – Skyre et al. (1991) assessed inter-rater reliability for diagnosing social phobia by asking three clinicians to assess 54 patient interviews obtained using the Structured Clinical Interview (SCID-I). There was high inter-rater agreement (+.72) showing that the diagnosis of phobia is reliable. SCID is a semi-structured interview. It requires extensive training to administer, which may account for the high reliability. Such scales take 1-2 hours to complete. The alternative is to use shorter, structured, self-administered scales. These are popular for specific phobias, for example the Munich Diagnostic Checklist (MDC). Hiller et al. (1990) reported satisfactory to excellent diagnostic agreement in a test-retest study using the MDC.

However reliability is not always found to be high. Kendler et al. (1999) used face-to-face and telephone interviews to assess individuals with phobias. Over a one-month interval (test-retest) they found a mean agreement of +.46. Reliability over the long term (eight years) was even lower, at +.30.

Reasons for low reliability – Kendler et al. (1999) suggest that the low reliability found in their study might be due to several factors. First, it might be due to participants’ poor recall of their fears – for example people tend to over-exaggerate fears when recalling previous distress. Second, low reliability might be due to the different decisions made by interviewers when deciding if the severity of a symptom does or does not exceed the clinical threshold for a symptom; one clinician might conclude that a symptom is clinically significant, whereas another might conclude that the severity does not exceed the clinical threshold and therefore a diagnosis is not made.

validityValidity refers to the extent to which a diagnosis represents something that is real and distinct from other conditions, the extent that a classification system such as DSM measures what it claims to measure. Reliability and validity are inextricably linked because a diagnosis cannot be valid if it is not reliable.

Comorbidity is the extent to which two (or more) conditions co-occur. If they do tend to co-occur this suggests that they are not separate entities, and therefore the diagnostic category is not very useful, for example, when deciding what treatment to advise. Research has found high levels of comorbidity between social phobias, animal phobias and generalised anxiety disorder, and also with depression (e.g. Kendler et al., 1993). Eysenck (1997) reported that up to 66% of patients with one anxiety disorder are also diagnosed with another, suggesting that anxiety disorders may be more appropriately grouped together.

Demonstrating validity of methods of diagnosis – There are various methods used to demonstrate the validity of a questionnaire/interview used to diagnose phobic disorders. For example:

• Concurrent validity establishes validity by comparing one method with another, previously validated, method. For example Mattick and Clarke (1998) showed that their Social Phobia Scale (SPS) correlated well with other standard measures (varying between +.54 and +.69).

• Construct validity measures the extent to which a test measures a target construct. For example the Social Phobia and Anxiety Inventory (SPAI) correlates well with behavioural measures of social phobia (e.g. ease of public speaking) and lacks association with behaviours unrelated to social phobia (Beidel et al., 1989).

The implications of low reliability and/or validity – In order to conduct research on the effectiveness of treatments for phobic disorders, researchers require a reliable and valid means of assessing the disorders in the first place. Therefore diagnosis and classification is critical in what we will consider on the following spreads.

diagnoSiS by comPuterComputerised scales for assessing phobic

and other disorders offer many advantages. Kobak et al. (1993) suggest that this includes ease of administration, cost-effectiveness and increased reliability because there is less opportunity for the administrator to affect the responses that are given. In addition, people with social phobias might prefer to answer without the presence of another person because of their fears of negative evaluation. However Heimberg et al. (1999) suggest that validity may be reduced with such measures because a skilled clinician plays an important role in facilitating the disclosure of troubling information, whereas this can be more easily avoided when ‘talking’ to a computer.

Rosenhan (1973) conducted a classic study on the unreliability of psychiatric diagnoses. This study is described on page 163.

The Japanese recognise a unique social phobia – taijin-kyofusho – which is the fear of embarrassing others in a social situation.

…1 Outline three clinical characteristics of phobic disorders.

…2 Outline two issues relating to reliability in the diagnosis/classification of phobic disorders and two relating to validity.

…3 Use this material to write a 600-word answer (in total) to the following two-part question:

(a) ‘Outline clinical characteristics of phobic disorders.’ (6 marks)(b) ‘Explain issues of reliability and validity associated with the classification and diagnosis of phobic disorders.’ (3 marks + 16 marks)

CAN YOU…? No.11.1

cultural differenceS in diagnoSiSOne of the key factors in deciding on a

diagnosis of a phobic disorder is the extent to which the fear would be considered to interfere with normal functioning as well as whether it is extreme in the context of a particular culture. This means that cultural ideas about ‘normal functioning’ and ‘normal’ fears are likely to affect any diagnosis.

Judgements may also vary with respect to culturally-relative disorers. A good example of this is provided by taijin-kyofusho (TKS), a culturally distinctive phobia recognised in Japan (and which is listed in DSM as a culture-bound syndrome). This is a social phobia where an individual has a fear of embarrassing others in social situations. An individual with such a condition would not be diagnosed in this country as having a social phobia, illustrating the effect of cultural experiences on the diagnosis of a disorder.

Most people associate ‘phobias’ with fear of spiders or snakes, but take a look at phobialist.com which lists every imaginable phobia from ablutophobia (fear of washing) to zemmiphobia (fear of the great mole rat – pictured above).

What we now refer to as ‘mental disorders‘ have been studied since medical records first began. Most forms of mental disorder are categorised into

groups according to their common symptoms, in diagnostic manuals such as the Diagnostic and Statistical Manual of Mental Disorders (DSM) and the International Classification of Diseases (ICD). DSM is produced in America whereas ICD was developed in Europe. In the UK, diagnosis is carried out using both DSM and ICD. At the start of the twentieth century there were only a dozen recognised mental disorders. By the end of the century there were 372 listed on the latest version of DSM, referred to as DSM-IV-TR. The term ‘phobic disorders’ describes a wide range of phobias – cases of irrational fears that produce a conscious avoidance of the feared object or situation. Key features of such disorders are that a phobic is aware that their reaction is excessive and that the phobia interferes with normal everyday life.

DSM- IV -TR CR ITER IA fOR THE DIAgNOSIS Of SPECIf IC PHOBIAA Marked and persistent fear that is

excessive or unreasonable, cued by the presence or anticipation of a specific object or situation (e.g. flying, heights, seeing blood).

B Exposure to the phobic stimulus almost invariably provokes an immediate anxiety response such as a panic attack. In children the anxiety may be expressed as crying, tantrums, freezing or clinging.

C The person recognises that the fear is excessive or unreasonable. This feature may be absent in children.

D The phobic situation is avoided or endured with intense anxiety or distress.

E The avoidance, anxious anticipation, or distress in the feared situation interferes significantly with the person’s normal routine, occupation, social activities or relationships, and there is marked distress about having the phobia.

F In individuals under age 18 years the duration is at least six months.

G The anxiety, panic attacks or phobic avoidance is not better accounted for by another mental disorder, such as obsessive-compulsive disorder or post-traumatic stress disorder.

Types of specific phobia• Animal type (e.g. spiders,dogs).• Natural environment type (e.g.

heights, storms, water).• Blood/injection/injury type.• Situational type (e.g. aeroplanes,

lifts, enclosed places).• Other types (e.g. fear of choking or

contracting an illness, or, in children, fear of loud noises or costumed characters).

Adapted from the American Psychiatric Association (2000)

the characteriSticS of Phobic diSorderSPhobic disorders are included in the DSM within the category of ‘anxiety disorders’ – a group of mental disorders sharing the primary symptom of extreme anxiety. This group includes agoraphobia (fear of being in a place where escape is difficult) with or without panic disorder, specific phobia (see left), and social phobia (fear of situations involving social interaction), as well as obsessive-compulsive disorder, post-traumatic stress disorder and generalised anxiety disorder. This chapter will focus on the phobias.

the nature of phobic disordersMany people talk about having phobias but there is a difference between feeling anxious and having a case of ‘clinical’ phobia i.e. a phobia that meets a set of clinical criteria such as those given in the DSM (see left). Consider the following description:

The patient was a 28-year-old woman whose attacks of anxiety were triggered by the terrifying sensation of impending death. This feeling was so horrifying that she would clutch passers-by and beg them for help. These episodes were acutely embarrassing to her… Finally, her fear of experiencing these symptoms in public reached the point where she was unwilling to leave home without her husband’ (from Sue et al., 1994).

diagnostic criteriaA clinical diagnosis of a phobic disorder is only made if there is no other possible physiological cause (e.g. substance abuse) or if the symptoms cannot be better accounted for by another disorder. The individual recognises that their behaviour is unreasonable – this is an important distinction between a phobia and a delusional mental illness (such as schizophrenia) where the individual is not aware of the unreasonableness of their behaviour. The key characteristic that distinguishes a clinical phobia from a mere ‘fear’ is the degree to which an individual’s functioning is impaired by the disorder.

Agoraphobia is a fear of being trapped in a public place or situation where escape may be difficult or embarrassing. It can occur alone or with panic disorder. A clinical diagnosis of agoraphobia with panic disorder is made if an individual experiences repeated unexpected panic attacks and, over the period of a month, the individual is persistently concerned about having such attacks or worries about the possible consequences of the attacks (e.g. losing control, having a heart attack).

Specific phobias are fears about specific objects or situations. These are the most common anxiety disorders. The clinical criteria for a diagnosis of a specific phobia are listed on the left. The two basic components are that the fear is triggered by a specific stimulus and that it is out of proportion to what is reasonable. Phobias in children are more commonplace, so criterion F sets up a six-month requirement for their diagnosis.

Social phobias are related to the more normal anxieties that we all feel when having to, for example, speak in public. In social phobia, such anxiety is so severe that it impairs everyday life. A distinction is made between performance anxiety and social anxiety. Performance anxiety includes giving a talk, using a public toilet or eating a meal in a restaurant. Social anxiety is similar to extreme shyness. In both cases the feared social situation invariably provokes anxiety and may be accompanied by a panic attack.

PANIC ATTACKSPanic attacks are a common symptom associated with phobias, especially agoraphobia. A panic attack (or panic disorder) involves physical symptoms such as a pounding heart, difficulty breathing, dizziness and stomach upset. In addition there are psychological symptoms such as a sense of terror, perceptual distortions and fear of dying.

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biological exPlanationS commentary

Phobias are among the most common mental disorders. Statistics suggest that about 4% of the adult population suffer from phobias, though this rate

varies from 2% (ONS, 2000) to 13% in one US survey (Stern, 1995).Anxiety and fear are natural and adaptive responses, and therefore have

a biological basis (part of the study of stress AS level). This might lead us to expect that abnormal fears and anxieties are also biologically based. This spread looks at the evidence for inheriting phobic disorders and the evolutionary explanation for such disorders.

What is a concordance rate? In a sample of, for example, 100 twin pairs, one twin of each pair has a phobic disorder. The number of times the other twin also shows the illness determines the concordance rate, so if 40 have phobic disorders, then the concordance rate is 40%.

biological exPlanationS of Phobic diSorderS

genetic factorsFamily and twin studies provide modest support for the genetic basis of phobic disorders, however there is considerable variability between disorders – Kendler et al. (1992) estimated a 67% heritability rate for agoraphobia, 59% for blood/injury, 51% for social phobias and 47% for animal phobias. However, other studies find even less support for genetic explanations. Torgerson (see facing page), for example, actually only found 31% concordance for MZ twins in terms of anxiety disorders, and almost no concordance for DZ twins.

One of the problems with family and twin studies is that they fail to control for shared environmental experiences. For example MZ twins are likely to share more similar experiences (environments) than DZ twins because, for example, they are likely to have more similar interests. One way to control for shared environment is to use studies of twins reared apart, but such studies have not been conducted with phobic disorders.

The diathesis-stress model – Even at the highest rates it is clear that phobic disorders are not solely genetic and have some considerable experiential component. This combination can be described by the diathesis-stress model – genetic factors predispose an individual to develop phobias but life experiences play an important role in triggering such responses. It is important to remember the comorbidity between phobias and depression (discussed on the previous spread), which means that genetic factors may actually predispose individuals to a range of different mental disorders.

What is inherited? Evidence has been accumulated to support the possible physiological differences between phobic and normal individuals. For example, brain-scanning techniques have been used to measure the density of dopamine re-uptake sites (i.e. areas in the brain where dopamine levels are controlled). Tiihonen et al. (1997) found a significantly lower number of such sites in patients with social phobia than in normal controls. This low number of sites would be likely to lead to abnormally low levels of dopamine.

Additional support comes from studies of behavioural inhibition (see box above) and the fact that successful drug therapies for phobics include drugs that block activity of the adrenergic system (beta-blockers) and thus reduce the symptoms of anxiety. However none of this is evidence that such differences actually cause the disorder in the first place. Drugs may, for example, be treating symptoms that have arisen as an effect rather than the cause of phobias.

an evolutionary approachPrepotency – Öhman and Soares (1994) provided evidence for prepotency effects. ‘Masked’ pictures were constructed of feared objects (snakes or spiders) in such a way that the animals in the pictures were not immediately recognisable. Participants who were fearful of snakes or spiders showed greater gSR (indicates arousal of the autonomic nervous system) when briefly shown ‘masked’ pictures compared to viewing neutral pictures or when compared to non-phobic participants. This shows that important components of phobic responses are set in motion before the phobic stimulus is represented in awareness, and these could be prepotent signals.

Preparedness – The two important predictions arising from the concept of preparedness are (a) that we learn certain fears more readily, and (b) that such fears are harder to unlearn. Laboratory studies typically condition fear responses by pairing an unconditioned stimulus (e.g. electric shock) with a conditioned stimulus. The conditioned stimulus is either a photograph of a ‘prepared’ stimulus (e.g. snake) or an ‘unprepared’ stimulus (e.g. flowers). McNally (1987) concluded that although there was firm evidence for enhanced resistance to extinction of fear responses conditioned by ‘prepared’ stimuli, evidence for rapid acquisition was, at best, equivocal.

This led Davey (1995) to propose a simpler explanation – expectancy biases. An expectancy bias is an expectation that fear-relevant stimuli (such as dangerous situations or past experience of unpleasantness) will produce negative consequences in the future. There is therefore no need to invoke past evolutionary history. This explains certain anomalous data such as the lack of rapid acquisition of phobias and the acquisition of ‘modern’ phobias (e.g. phobia of hypodermic needles).

Clinical phobias – Do the concepts of prepotency and preparedness explain anxiety disorders? Much of the research we have looked at is concerned with avoidance responses rather than clinical disorders (i.e. phobias that fulfil the clinical characteristics for phobic disorders). Studies of patients suffering from disabling disorders do not support the preparedness explanation. For example, Merckelbach et al. (1988) found that most of the clinical phobias in their sample were rated as non-prepared rather than prepared. In addition, research has found that clinical phobias do not display the suddenness of onset and resistance to treatment predicted by preparedness (de Silva et al., 1977).

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…1 Describe two biological explanations of phobic disorders in 100-150 words each.

…2 Outline three critical points for each explanation, including (a) the critical point being made, (b) your evidence for this criticism, and (c) how this criticism affects that explanation.

…3 Choose two critical points from the synoptic toolkit (see Introduction, page ix) relevant to each explanation and elaborate on it in 50 words. Ensure that any synoptic points are fully contextualised.

…3 Use this material to write a 600-word answer to the question: ‘Discuss two or more biological explanations of phobic disorders.’ (9 marks + 16 marks)

CAN YOU…? No.11.2

behavioural inhibitionKagan (1994) identified an infant temperamental

type that he described as ‘behavioural inhibition’ – infants who tend to withdraw from unfamiliar people, objects and situations. He suggested that this behaviour had a genetic basis.

Longitudinal studies have followed children who showed signs of behavioural instability at birth. At primary school age such children were found to have higher ANS activity and also the largest number of specific fears. Similar results were found when looking at children whose parents suffered from panic disorder. further follow-up studies found that both these groups of children developed significantly more anxiety disorders, supporting the hypothesis that behavioural inhibition to unfamiliar things or situations is genetically based and a risk factor for anxiety disorders (Biederman et al., 1993).

cultural differenceSThere are significant

differences in the kind of phobias reported by different cultural groups. for example Brown et al. (1990) found that phobic disorders were more common among African American than white American participants even when socioeconomic factors were controlled. This shows that environmental/social factors are important in determining aspects of phobias.

genetic factorsFamily studies – Research shows that having a family member with a phobic disorder increases the risk that an individual develops a similar disorder. (The family member who already has the disorder is called the proband). For example, Fyer et al. (1995) found that probands had three times as many relatives who also experienced phobias as normal controls. Solyom et al. (1974) found that 45% of phobic patients had at least one relative with the disorder, compared to a rate of 17% of non-phobic controls. Relatives usually have the same disorder as the proband, for example Ost (1989) found that 64% of blood phobics had at least one relative with the same disorder.

Twin studies – Comparisons can be made between identical (or monozygotic, MZ) twins and non-identical (or dizygotic, DZ) twins. As MZ twins are genetically identical, a closer concordance rate between MZ twins and DZ twins is evidence for a genetic basis for phobic disorders. Torgersen (1983) compared MZ and same-sex DZ twin pairs (total number of twins was 85) where one twin (the proband) had an anxiety disorder with panic attacks. Such disorders were five times more frequent in MZ twin pairs.

What is inherited? It may be that people inherit an oversensitive fear response. People with phobias often respond to normal situations with abnormal levels of anxiety, for example having panic attacks. Once an individual has experienced a panic attack in a particular situation this creates further anxiety that the same will happen in the future.

The oversensitive fear response can be explained in terms of the functioning of the autonomic nervous system (ANS). In some individuals there may be abnormally high levels of arousal in the ANS which leads to increased amounts of adrenaline. This is called the adrenergic theory. Additional theories concern dopamine pathways in the brain that predispose some people to be more readily conditioned to acquire phobias easily (see the behavioural explanation of phobias on the next spread). Finally, abnormal serotonin activity has been suggested as a cause of oversensitive fear response because it modulates those areas of the brain involved in the fear response, such as the amygdala.

an evolutionary approachThere are three explanations that each offer a way to explain the uneven distribution of phobias, i.e. that some fears are more common than others.

Ancient fears and modern minds – Some stimuli are more likely to be feared than others, such as snakes, heights, storms, darkness, strangers, separation and leaving the home range. These might be referred to as ancient fears, in that these stimuli reflected very real danger to our ancestors. Most modern-day phobias are exaggerations of these ancient fears (Marks and Nesse, 1994). Many other stimuli, such as leaves, stones and shallow water, were also part of our ancestral environment, yet because they posed no significant danger, are rarely feared. By the same token, things that are dangers today, such as motor cars, electricity or guns, rarely develop into phobias because they have not been around enough to have influenced our adaptive selection.

Prepotency – Experiencing anxiety after an event has happened would not be an adaptive response, therefore animals have evolved to respond to potential threats. Those ancestors who were able to respond appropriately to ‘ancient’ threats were more likely to survive and pass on their genes to subsequent generations. Natural selection, therefore, has shaped our nervous system so that we attend more to certain cues than others. For example, we may respond more anxiously to sudden noises or to visual stimuli that are more snake-like, a phenomenon known as prepotency (something that has power prior to direct experience). Prepotent fears are more likely to develop into phobias.

Preparedness – In addition to the idea of prepotency, it is a more flexible arrangement to have an innate readiness to learn about dangerous situations rather than inheriting rigid behavioural responses to specific situations. The concept of biological preparedness (Seligman, 1970) accounts for this. Seligman argued that animals, including humans, are biologically prepared to rapidly learn an association between particular (i.e. potentially life-threatening) stimuli and fear. Once learned, this association is difficult to extinguish. What is inherited is therefore the predisposition to form certain associations rather than others, instead of inheriting a fixed fear of certain things. For example, when an infant sees a stranger, they first look at their mother to gauge her response. Fear in the mother is likely to produce a fearful reaction from the infant (Marks, 1987). The infant has inherited a predisposition to learn this fear through observation rather than having an innate fear of strangers. However, such learning does not take place in response to all stimuli. Rhesus monkeys rapidly develop a fear of snakes if they see another rhesus monkey showing fear towards a snake, however the same rapid association is not made if another rhesus monkey

shows fear towards a flower (Mineka et al., 1984).

The caterpillar of the convolvulus hawk moth has snake-head markings on its back end, an example of a prepotent signal which deters predators.

Bennett-Levy and Marteau (1984) have suggested that prepotent signalling in humans is achieved by an innate readiness to fear animals whose form is most different from that of humans, in terms of texture of skin and number of limbs. However they found, when asking participants to rate a list of animals for fearfulness, ugliness and strangeness, that some animals (such as a slug) should have been highly feared, but weren’t.