Shyness: relationship to social phobia and other psychiatric disorders

Behaviour Research and Therapy 41 (2003) 209–221 www.elsevier.com/locate/brat

Shyness: relationship to social phobia and other psychiatric disorders Nancy A. Heiser ∗, Samuel M. Turner, Deborah C. Beidel Maryland Center for Anxiety Disorders, Department of Psychology, University of Maryland, College Park, MD 20742, USA

Abstract The relationship between shyness, social phobia and other psychiatric disorders was examined. The prevalence of social phobia was significantly higher among shy persons (18%) compared with non-shy persons (3%). However, the majority of shy individuals (82%) were not socially phobic. A significant and positive correlation was found between the severity of shyness and the presence of social phobia, but the data suggest that social phobia is not merely severe shyness. Social phobia was also positively and moderately correlated with introversion and neuroticism. Thus, shy persons with social phobia were shyer, more introverted, and more neurotic than other shy people, but none of these factors was sufficient to distinguish shy persons with social phobia from those without social phobia. The proportion of the shy group with psychiatric diagnoses other than social phobia was significantly higher than among the non-shy group, indicating that various diagnostic categories are prominent among the shy. The results are discussed in terms of the overlap in shyness and social phobia and the relationship of shyness to other psychiatric diagnoses and personality dimensions.  2002 Elsevier Science Ltd. All rights reserved.

1. Introduction Social phobia and shyness are terms used to describe those who are reticent in social situations, and there has been considerable speculation on their relationship (e.g., Beidel & Turner, 1999; Turner, Beidel, & Townsley, 1990). Although social phobia is a clinical disorder defined in the Diagnostic and Statistical Manual of Mental Disorders—Fourth Edition (DSM-IV) (1994) and shyness is a less well-defined lay term, descriptions of the two syndromes are remarkably similar. The DSM-IV defines social phobia as “a marked and persistent fear of one or more social situ-

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ations in which the person is exposed to unfamiliar people or to possible scrutiny by others” (p. 416). The disorder ranges from rather circumscribed performance anxiety (specific or circumscribed subtype) to the more common pattern of anxiety in most social settings (generalized subtype). Interestingly, the description of shyness is not all that different, particularly the most recent characterizations of the condition. Shyness has been described as anxiety and discomfort in social situations, particularly those involving evaluation by authority figures (Crozier, 1979); discomfort and inhibition in interpersonal situations (Henderson & Zimbardo, 1998); and fear of negative evaluation by others (Buss, 1985). Clearly, one can see from these brief descriptions that the behaviors associated with the two conditions are similar. Indeed, examination of the extant literature reveals that social phobia and shyness share similar symptomatology. For example, Turner et al. (1990) examined studies that described the characteristics of social phobia and shyness. Based on these indirect comparisons, they found that shyness and social phobia appeared to be similar in terms of somatic (e.g., trembling, sweating, blushing), cognitive (e.g., fear of negative evaluation by others), and behavioral symptoms (e.g., distress in and avoidance of social situations). However, shyness was noted to differ markedly from social phobia in a number of ways. The most striking difference was in prevalence rate. Based on numerous studies, the prevalence of shyness was far greater than that of social phobia. The 12-month prevalence rate for social phobia in the Epidemiologic Catchment Area study (ECA; Schneier, Johnson, Hornig, Liebowitz, & Weissman, 1992) was estimated to be about 3%, but in the more recent National Comorbidity Study (NCS; Kessler et al., 1994), the estimated 12-month prevalence rate was 8%. The variability in these prevalence estimates at least partly reflects differences in the assessment and sampling methodology used in the two studies (Beidel & Turner, 1998). Prevalence estimates of shyness are much higher than those of social phobia, ranging from 20 to 48% (Carducci & Zimbardo, 1995; Henderson & Zimbardo, 1998; Lazarus, 1982; Zimbardo, 1977; Zimbardo, Pilkonis, & Norwood, 1975). Thus, although variability in the prevalence estimates of both shyness and social phobia exist, the prevalence estimates of shyness consistently are markedly higher than those of social phobia. There also is evidence that shyness and social phobia may differ in other important ways as well. For example, shyness is often a transitory condition (Beidel & Turner, 1999; Bruch, Giordano, & Pearl, 1986; Zimbardo et al., 1975), whereas social phobia is thought to be a chronic, unremitting condition (Turner & Beidel, 1989). In addition, although social phobia and shyness are both associated with emotional and social difficulties, preliminary evidence suggests that those who are shy, on average, do not experience the degree of daily impairment that is experienced by social phobics (Turner et al., 1990). However, because this evidence is based on indirect comparisons, the extent to which these conditions can be distinguished based on the degree of impairment will need to be determined by future direct comparison studies. Despite some effort to delineate the boundary between the two conditions, the relationship between social phobia and shyness remains blurred. One hypothesis is that the two conditions are completely different (Carducci, 1999). Carducci (1999) concluded that “shyness is also not a social disease such as social phobia or avoidant personality disorder…Shyness is not listed in the Diagnostic and Statistical Manual of Mental Disorders IV…because it’s not a mental illness, merely a normal facet of personality” (p. 6). A second hypothesis is that the conditions are essentially the same. Rapee (1998) noted that “many words and terms have been used to describe

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shyness, including social phobia, social anxiety, avoidant personality disorder…they all refer basically to the same thing” (p. xi). Yet a third hypothesis is that social phobia is an extreme form of shyness. Marshall and Lipsett (1994) concluded that shyness is a form of social anxiety and generalized social phobia in particular is an extreme form of shyness. Consistent with this view, Henderson and Zimbardo (1998) described shyness as varying “from mild social awkwardness to totally inhibiting social phobia” (p. 497). A fourth hypothesis put forth by Heckelman and Schneier (1995) is that shyness is a more heterogeneous category than social phobia, that it may overlap with mild cases of social phobia, and that it may also “extend outside of the social phobia spectrum” (p. 11). Similarly, Beidel and Turner (1999) concluded that the overlapping behavioral features of shyness and social phobia support the notion that a relationship between them exists, but the specific nature remains to be elucidated. In their proposed model of the relationship among shyness, social phobia, and other constructs of social reticence (i.e., behavioral inhibition and social isolation), social phobia represents a relatively small group of individuals, and one that overlaps with shyness, behavioral inhibition, and social isolation. Beidel and Turner (1999) suggested that shyness might be a contributing but not a necessary factor for the development of social phobia. Consistent with this view, Stemberger, Turner, Beidel, and Calhoun (1995) found that a history of childhood shyness was more common in the backgrounds of those with social phobia than of those without psychiatric disorders. However, they suggested that the presence of a predispositional factor such as shyness or behavioral inhibition does not necessarily lead to the development of social phobia. Thus, Beidel and Turner (1999) concluded that, although there appears to be a relationship between these two conditions characterized by social reticence, the exact relationship between them is unclear. The current study was designed to examine the relationship between shyness and social phobia by directly comparing the two conditions in the same sample. Specifically, the study examined the overlap in social phobia and shyness, the relationship between the severity of shyness and social phobia, and the relationship of shyness to other disorders. In addition, the relationship between shyness, social phobia, neuroticism, and introversion was examined.

2. Method 2.1. Participants The sample consisted of 200 students at the University of Maryland, College Park who were enrolled in an introductory psychology course. The course required students to participate in research studies as participants or to write a research paper. The students in this study chose to participate in research studies. The sample consisted of the first 200 introductory psychology students who signed up for the study. The sample included 119 women (59.5%) and 81 men (40.5%), with a mean age of 19.5 years. Of the 200 participants, 53.5% were Caucasian, 17.5% were Asian, 17.0% were African-American, 10.0% were Hispanic, and 2.0% were of other racial and ethnic groups.

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2.2. Assessment 2.2.1. Determination of shyness The Revised Cheek and Buss Shyness Scale (RCBS) (Cheek, 1983) was used to determine level of shyness. The RCBS is a 13-item self-report survey that has a scale range of 13 to 65. Shy individuals are those with scores of 34 and above (Cheek, 1983). The RCBS, which has been characterized as “the measure of choice” in shyness studies (Leary, 1991), assesses both affective and behavioral aspects of shyness. Studies of the RCBS reported internal consistency of 0.90 (Cronbach’s alpha); an average inter-item correlation of 0.39; and a 45-day test–retest reliability of 0.88 (Leary, 1991). In addition, the RCBS has adequate convergent validity, correlating highly with many other measures of shyness, including other self-report measures and aggregated ratings of shyness by friends and family (Leary, 1991). 2.2.2. Determination of DSM-IV, Axis I psychiatric diagnoses The Composite International Diagnostic Interview, Automated Version (CIDI-Auto) (1993) was used to determine DSM-IV Axis I disorders during the past year. The CIDI-Auto was self-administered. The CIDI, a fully structured diagnostic instrument, was developed for use by lay interviewers in epidemiological studies. Sufficient psychometric properties have been demonstrated when administered by a clinician or layperson and when self-administered (Blanchard & Brown, 1998; Peters & Andrews, 1995; Wittchen, 1994). Inter-rater reliability as assessed by kappa was greater than 0.9 for the majority of disorders and greater than 0.7 for all disorders (Wittchen, 1994). Validity studies have found adequate concordance rates between CIDI and clinicians’ checklists (kappa ⫽ 0.76) and between CIDI and independent clinicians’ diagnoses (kappa values in the range of 0.73–0.83; Wittchen, 1994). Studies of the automated version have shown excellent test–retest reliability and acceptance of the computerized format by participants (Andrews & Peters, 1998). To assess the validity of the CIDI, a subset of participants (n ⫽ 32) were interviewed using a semi-structured interview, the Anxiety Disorders Interview Schedule for DSM-IV (ADIS-IV) (Di Nardo, Brown, & Barlow, 1995). These participants were interviewed by clinical psychology graduate students who had extensive experience of conducting ADIS-IV interviews. The interviewers were unaware of diagnoses from the CIDI as well as the results of all other assessments. The participants were students in the original sample who agreed to participate in this part of the study in exchange for research credit in their introductory psychology class. The characteristics of the subset of subjects did not differ from those of the other students in the study in terms of age, gender, and race/ethnicity (age: t(198) ⫽ 0.11, P ⬎ 0.05; gender: c2(1,n ⫽ 200) ⫽ 2.42, P ⬎ 0.05; ethnicity: Fisher’s Exact Test, P ⬎ 0.05). Kappa coefficients for the ADIS-IV and CIDI were as follows: any anxiety disorder, ␬ ⫽ 0.73; social phobia, ␬ ⫽ 0.80; and generalized anxiety disorder, ␬ ⫽ 0.67. Other diagnoses were assigned too infrequently for valid kappa coefficients to be calculated. These results provide support for the validity of the diagnoses derived from the CIDI. In addition, 25% of the interviews were randomly selected to be rated by a second independent clinician who was blind as to diagnosis. Kappa coefficients were as follows: anxiety disorder, ␬ ⫽ 0.71; and social phobia, ␬ ⫽ 0.71. Other diagnoses were assigned too infrequently for valid kappa coefficients to be calculated.

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2.2.3. Determination of DSM-IV, Axis II psychiatric diagnoses Axis II diagnoses were determined with the Personality Diagnostic Questionnaire (PDQ-4; Hyler, 1998). The PDQ-4 is a self-report, 99-item, forced-choice (true/false format) questionnaire. Internal reliability coefficients ranged from 0.56 to 0.83, with coefficients for only two personality disorders falling below 0.60 (Hyler et al., 1989). A study of test–retest reliability found a kappa of 0.70 for presence of a personality disorder and adequate test–retest reliability overall for specific personality disorders (Hurt, Hyler, Frances, Clarkin, & Brent, 1984). Studies of the validity of the PDQ using semi-structured interviews as the standard found that the instrument tends to yield a high false positive rate (low specificity) and a low false negative rate (high sensitivity). Although self-report personality assessment instruments in general have this drawback and should not be a substitute for clinical assessment in the clinic setting (Hyler et al., 1989), they are efficient instruments for screening for personality disorders (e.g., Hyler et al., 1990). Therefore, this instrument was considered to be adequate for the purposes of this study. 2.2.4. Personality characteristics The Eysenck Personality Inventory (EPI; Eysenck & Eysenck, 1968) is a 57-item, self-report questionnaire that measures two independent and pervasive dimensions of personality: extroversion–introversion and neuroticism–stability. Test–retest reliabilities are satisfactory, ranging from 0.84 to 0.94. The split-half reliabilities ranged from 0.74 to 0.91. Other studies found that EPI scores for the two factors correlated highly with other instruments purporting to measure these dimensions (Eysenck & Eysenck, 1968). 2.3. Procedures Informed consent was obtained from all participants prior to the start of the study. Students in groups of 10 to 20 completed the assessment instruments. A follow-up procedure was conducted for all participants whose responses to the CIDI suggested they might have a psychiatric diagnosis. In the follow-up interview, a clinician asked additional questions to clarify the nature and extent of the problems endorsed on the CIDI. As needed, participants were informed about assessment and treatment options and referrals were made.

3. Results Fig. 1 shows that the shyness scores of the entire sample were normally distributed (skewness statistic ⫽ 0.12). Based on the RCBS cutoff score of 34, 96 (48.0%) of the 200 participants were classified as shy. Within the two groups, those classified as shy had a mean RCBS score of 42.9, which was significantly higher than the mean RCBS score of 25.0 for the non-shy group [t(198) ⫽ 21.68, P ⬍ 0.05]. Gender, ethnicity, and age of the shy and non-shy groups were very similar. Fifty-five per cent of the shy group were women compared with 64% of the non-shy group, a difference that was not statistically significant [c2(1,n ⫽ 200) ⫽ 1.41, P ⬎ 0.05]. There was no difference between groups with respect to race and ethnicity (Fisher’s Exact Test, P ⬎ 0.05), with about one-half of

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Fig. 1. Distribution of shyness scores. Based on the Revised Cheek and Buss Shyness Scale (RCBS).

the subjects in each group being Caucasian. The average age among the shy group was 19.8 years compared with 19.3 years in the non-shy group [t(198) ⫽ 1.08, P ⬎ 0.05]. Of the total sample (200 participants), 20 (10%) met criteria for social phobia. Ten per cent is fairly close to, but slightly higher than, the most recent national 12-month prevalence estimate of social phobia (8%; Kessler et al., 1994). Seventy-five per cent of the participants with social phobia met criteria for the generalized subtype and 25% met criteria for the specific subtype. 3.1. Overlap of shyness and social phobia Among the 96 shy participants, only 17 (17.7%) met criteria for social phobia. Seventy-nine (82.3%) were not diagnosed with social phobia. Thus, the vast majority of those in the shy group were not socially phobic. However, the diagnosis of social phobia occurred significantly more often among the shy than among the non-shy [17.7% vs. 2.9%; c2(1,n ⫽ 200) ⫽ 12.19, P ⬍ 0.05]. In summary, most socially phobic persons were shy, but they represented only a small minority of the shy group. Among those who were diagnosed with social phobia, 15% (n ⫽ 3) were not shy. 3.2. Severity of shyness and social phobia Using the total sample (n ⫽ 200), RCBS scores and social phobia were moderately and positively correlated (Bi-serial correlation r ⫽ 0.39, P ⬍ 0.05). Among the shy group only, this same relationship was found (Bi-serial correlation r ⫽ 0.47, P ⬍ 0.05). That is, the more severe the level of shyness, the greater the likelihood of a diagnosis of social phobia. The average RCBS score among shy individuals with social phobia was 49.1 compared with 41.6 among the shy without social phobia [t(94) ⫽ 5.19, P ⬍ 0.05]. Although there is a low-moderate correlation between shyness severity and social phobia, the distribution of RCBS scores of the shy group with social phobia overlapped substantially with those of the shy group without social phobia. Furthermore, shy persons with social phobia had RCBS scores ranging from 40 to 62 and shy persons without social phobia had RCBS scores

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ranging from 34 to 53. Finally, among the shy group, severity of shyness explained only 22% of the variance of social phobia (r2 ⫽ 0.22). These data suggest that a positive relationship exists between severity of shyness and social phobia, but those with social phobia cannot simply be characterized as extremely shy. 3.3. Psychiatric comorbidity in the shy group Among shy persons, 55% met criteria for an Axis I disorder. Half of the shy persons (50%) met criteria for an Axis II disorder, and over two-thirds (66.7%) of shy persons met criteria for an Axis I or an Axis II disorder. Shy persons were significantly more likely to have any type of disorder (an Axis I or Axis II disorder) compared with non-shy persons [66.7% and 42.3%, respectively; c2(1,n ⫽ 200) ⫽ 11.93, P ⬍ 0.05]. With respect to Axis I disorders, shy persons were more likely to have a diagnosis than the non-shy (Table 1). Specifically, 55.2% of the shy group had an anxiety, mood, or substancerelated disorder compared with 33.7% of the non-shy group [c2(1,n ⫽ 200) ⫽ 9.41, P ⬍ 0.05] Shy persons were more likely to have a mood disorder, social phobia, and other anxiety disorders Table 1 Psychiatric diagnoses among shy and non-shy participants (n ⫽ 200) Shy participants (n ⫽ 96)

Non-shy participants (n ⫽ 104)

Number

Percentage

Number

Percentage

Axis I diagnoses Any Axis I diagnosis Social phobia Other anxiety disorder Mood disorder Substance-related disorder

53 17 22 26 18

55.2 17.7 22.9 27.1 18.8

35 3 10 16 19

33.7 2.9 9.6 15.4 18.3

Axis II diagnoses Any personality disorder Avoidant personality disorder Antisocial personality disorder Borderline personality disorder Dependent personality disorder Histrionic personality disorder Narcissistic personality disorder Obsessive–compulsive personality disorder Paranoid personality disorder Schizoid personality disorder Schizotypal personality disorder

48 34 0 13 3 3 10 15 13 3 5

50.0 35.4 0.0 13.5 3.1 3.1 10.4 15.6 13.5 3.1 5.2

19 10 2 1 0 2 2 8 5 1 0

18.3 9.6 1.9 1.0 0.0 1.9 1.9 7.7 4.8 1.0 0.0

Any Axis I or Axis II diagnosis

64

66.7

44

42.3

Diagnosis

Classification and diagnoses based on the Composite International Diagnostic Interview (CIDI), the Revised Cheek and Buss Shyness (RCBS) scale, and the Personality Diagnostic Questionnaire, Version 4 (PDQ-4).

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than the non-shy [mood disorder: c2(1,n ⫽ 200) ⫽ 4.12, P ⬍ 0.05; social phobia: c2(1,n ⫽ 200) ⫽ 12.19, P ⬍ 0.05; other anxiety disorder: c2(1,n ⫽ 200) ⫽ 6.57, P ⬍ 0.05]. There were no significant differences in rates of substance-related disorders [c2(1,n ⫽ 200) ⫽ 0.01, P ⬍ 0.05]. When examining Axis II disorders, a Bonferroni correction was used to control the experimentwise error rate because multiple comparisons were made. Therefore, a significance level of 0.005 was used. The shy group was more likely than the non-shy group to have a personality disorder [50.0% and 18.3%, respectively; c2(1,n ⫽ 200) ⫽ 22.56, P ⬍ 0.005], with the most common diagnosis being avoidant personality disorder (35.4% of the shy group and 9.6% of the non-shy group). Other personality disorders were relatively infrequent, but there were significant differences with respect to a diagnosis of borderline personality disorder [13.5% and 1.0%; c2(1,n ⫽ 200) ⫽ 12.14, P ⬍ 0.005], narcissistic personality disorder [10.4% and 1.9%; c2(1,n ⫽ 200) ⫽ 6.39, P ⬍ 0.005], paranoid personality disorder [13.5% and 4.8%; c2(1,n ⫽ 200) ⫽ 4.65, P ⬍ 0.005], and schizotypal personality disorder (5.2% and 0.0%; Fisher’s Exact Test, P ⬍ 0.005). In each case, the shy had higher prevalence of these personality disorders than the non-shy. 3.4. Comorbidity, shyness, and social phobia With respect to Axis I disorders of mood, anxiety, or substance use, shy persons who also met criteria for social phobia were not more likely to have Axis I conditions than shy persons without social phobia. Thus, having both shyness and social phobia was not associated with greater comorbidity for other Axis I disorders (mood disorder: Fisher’s Exact Test, P ⬎ 0.05; other anxiety disorder: Fisher’s Exact Test, P ⬎ 0.05; substance-related disorder: Fisher’s Exact Test, P ⬎ 0.05; Table 2). With respect to Axis II conditions, shy persons who also met criteria for social phobia were more likely to have Axis II conditions than shy persons without social phobia [c2(1,n ⫽ 96) ⫽ 8.65, P ⬍ 0.05]. The most common Axis II condition among the shy was avoidant personality disorder (APD). Among the shy and social phobic group, 76.5% met criteria for APD compared with 26.6% of those who were shy only [c2(1,n ⫽ 96) ⫽ 15.20, P ⬍ 0.05]. These results suggest that shy persons with social phobia and shy persons without social phobia are equally likely to Table 2 Psychiatric diagnoses among shy participants with and without social phobia (n ⫽ 96) Diagnosis

Other anxiety disorder Mood disorder Substance-related disorder Personality disorder Avoidant personality disorder

Shy with social phobia (n ⫽ 17)

Shy without social phobia (n ⫽ 79)

Number

Percentage

Number

Percentage

5 7 4 14 13

29.4 41.2 23.5 82.4 76.5

17 19 14 34 21

21.5 24.1 17.7 43.0 26.6

Based on the Composite International Diagnostic Interview (CIDI), the Revised Cheek and Buss Shyness (RCBS) scale, and the Personality Diagnostic Questionnaire, Version 4 (PDQ-4).

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have an Axis I disorder, but shy persons with social phobia were more likely to have a personality disorder (mostly APD). 3.5. Personality dimensions and shyness Using the EPI, analyses of introversion and neuroticism were conducted (Table 3). The shy group was significantly more introverted (less extroverted) and neurotic than the non-shy group [extroversion: 10.8 versus 15.3, t(198) ⫽ 8.31, P ⬍ 0.05; neuroticism: 12.9 versus 8.4, t(198) ⫽ 6.62, P ⬍ 0.05]. Similarly, those comorbid for social phobia and shyness were significantly more introverted and neurotic than shy persons without social phobia [extroversion: 8.4 versus 11.3, t(94) ⫽ 2.46, P ⬍ 0.05; neuroticism: 16.2 versus 12.2, t(94) ⫽ 3.16, P ⬍ 0.05]. Neuroticism was positively and moderately related to Axis I disorder (r ⫽ 0.50). This relationship held for the shy (r ⫽ 0.55) and less so for the non-shy, where the correlation was somewhat weaker (r ⫽ 0.36). Neuroticism was not significantly different among shy social phobics compared with shy persons with other Axis I disorders [16.2 versus 15.0, t(51) ⫽ 0.99, P ⬎ 0.05]. Thus, neuroticism did not appear to be related to social phobia specifically, but rather appeared to be associated with the presence of an Axis I disorder in general. Consistent with this finding, the correlation among the shy between neuroticism and social phobia of 0.31 is similar to the correlation between neuroticism and the presence of other Axis I disorders among the shy (0.33). Introversion was very weakly correlated with Axis I disorder (r ⫽ 0.12). However, introversion was significantly higher among social phobics who also were shy compared with shy persons with other Axis I disorders [8.4 versus 12.0, t(51) ⫽ 2.89, P ⬍ 0.05]. In summary, neuroticism was associated with the presence of an Axis I disorder of any kind and was not specific to those who were shy and/or socially phobic. However, social phobics were more introverted than other shy persons including those with other types of disorders. Thus, high introversion appeared to be more specifically related to social phobia than to other conditions.

Table 3 Introversion and neuroticism (means, with standard deviations in parentheses) Group

Extroversion (mean, SD)

Neuroticism (mean, SD)

Shy (n ⫽ 96) With social phobia (n ⫽ 17) Without social phobia (n ⫽ 79) With another Axis I disorderatfn:a (n ⫽ 36) Without an Axis I disorder (n ⫽ 43) Not shy (n ⫽ 104) Norms for college students

10.8 (4.5) 8.4 (4.2) 11.3 (4.4) 12.0 (4.2) 10.7 (4.6) 15.3 (3.1) 13.1 (4.1)

12.9 (5.0) 16.2 (3.6) 12.2 (5.0) 15.0 (4.5) 9.8 (4.2) 8.4 (4.6) 10.9 (4.7)

Based on the Eysenck Personality Inventory (EPI). Classification based on the Composite Diagnostic Interview (CIDI) and the Revised Cheek and Buss Shyness (RCBS) scale. Norms based on Eysenck and Eysenck (1968). a (atfn:a) Persons with an Axis I disorder but not social phobia.

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4. Discussion A major objective of this study was to shed light on the similarities and differences of shyness and social phobia, and several conclusions can be made at this time. The hypothesis that social phobia and shyness are completely separate conditions (i.e., Carducci, 1999) cannot be supported by these findings. The prevalence of social phobia among shy persons (18%) is significantly higher than among non-shy persons (3%). Also, the proportion of shy persons with social phobia is substantially higher than the 2–8% national prevalence estimates of social phobia in the general population (Kessler et al., 1994; Schneier et al., 1992), indicating that those who are shy have a much greater likelihood of meeting criteria for social phobia. This conclusion is strengthened even more by the finding that 35% of the shy sample met criteria for avoidant personality disorder, a condition whose boundary with social phobia is blurred (e.g., Turner, Beidel, & Townsley, 1992). Given these relationships, it seems clear that shyness and social phobia are at least related. A second hypothesis is that the two conditions are the same. This hypothesis is not supported by the findings because, of the shy group, only 18% met criteria for social phobia. Thus, 82% are shy but not socially phobic. The two conditions, then, are not identical. A third prominent hypothesis has been that social phobia is merely a more severe form of shyness (e.g., Henderson & Zimbardo, 1998; Rapee, 1998). The data here do not support this hypothesis as the findings indicate that although there is a positive and moderate correlation between severity of shyness and social phobia, there is substantial overlap in shyness scores between shy persons with social phobia and shy persons without social phobia. In addition, shyness severity only accounts for 22% of the variance in social phobia. Furthermore, some individuals with social phobia (15%) were not identified as shy, which could be taken as further evidence that those with social phobia are not simply extremely shy. However, this result needs to be interpreted cautiously because this finding might be attributable to the small sample size and measurement error. Nevertheless, based on the findings in this study, the relationship between the severity of shyness and social phobia is not strong enough to definitively conclude that social phobia is merely an extreme form of shyness. Yet a fourth major hypothesis is that there is overlap in shyness and social phobia, but that shyness is a much broader construct. The results of this study support this hypothesis as the findings show that shyness and social phobia are related conditions, but not the same condition. The vast majority of the shy group (82%) did not meet criteria for social phobia, but more of the shy met criteria for social phobia than the non-shy (see above). One might argue that a larger percentage of the shy sample will eventually become socially phobic, but this is viewed as unlikely because these participants had passed through the age of greatest risk for the onset of social phobia (i.e., mid-adolescence). Thus, it is unlikely that their future risk for developing the disorder is extremely high. In other words, if they were going to develop social phobia, most would have already developed the disorder. Thus, the percentages here are likely to remain rather stable. Overall, then, the fourth hypothesis (i.e., that shyness is a broad construct, associated with a number of different conditions) is the one most strongly supported by the current data. In fact, the data attesting to the heterogeneity of disorders among the shy are rather striking. First, although about one-third of those meeting shyness criteria had no disorder at all, the remaining two-thirds met criteria for some Axis I or Axis II condition. With respect to Axis I disorders, shy persons are more likely to have social phobia, other anxiety disorders, and mood disorders.

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The prevalence rates of anxiety and mood disorders among the shy are about twice those in the general population based on estimates from the National Comorbidity Study (Kessler et al., 1994). On the other hand, the rates of Axis I psychiatric disorders among the non-shy group generally did not vary substantially from the National Comorbidity Study estimates. Similarly, shy persons are more likely to have Axis II disorders, particularly avoidant personality disorder. Thus, it appears that shyness is related in unknown ways to general psychopathology, but it does not appear to be uniquely related to social phobia as has been speculated. The finding that shyness is related to psychopathology in a broad fashion is a new one, and one that has considerable potential importance. Heretofore, shyness has been considered to be basically a benign condition, but these findings suggest otherwise. What remains unclear is what makes those who are shy more likely to meet criteria for a diagnosable disorder. One possible explanation is that shyness is one manifestation of a broad temperamental condition related to differences in vulnerability to pathology. It cannot be determined from this study if shyness per se is the factor that accounts for this putative vulnerability or whether some other factor or factors are responsible. However, it is interesting that the shy group in this study is more neurotic than the non-shy, and neuroticism is related to the presence of Axis I disorders. Because neuroticism is known to be a vulnerability factor for general psychopathology (e.g., Duggan, Sham, Lee, Minne, & Murray, 1995) and shyness is positively correlated with neuroticism as found in this study and others (e.g., Jones, Briggs, & Smith, 1986), such a relationship should be explored. However, shyness and neuroticism are only moderately correlated and it would not appear that neuroticism alone could completely explain the relationship of shyness to other conditions. This casts some doubt on the likelihood that neuroticism alone is the common mediating factor. It also is possible that variables important for one condition might not be the critical one for another. Thus, for example, in this study introversion was more specific to social phobia than other Axis I conditions, and more related to social phobia than neuroticism. Finally, another possible reason that shy individuals appear to be more vulnerable to pathology than non-shy persons is that shyness itself is the effect of one or more conditions rather than the cause of pathology. Specifically, shyness may represent a range of cognitive, behavioral, and somatic features that are characteristic of, but not the cause of, multiple disorders. For example, shyness may be the result of rather than a cause of or risk for depression, social phobia, agoraphobia, avoidant personality disorder, and other disorders. Thus, shyness could be a behavioral consequence of these conditions rather than a risk factor for developing a pathological condition. To summarize, a key finding of this study is that shyness is related to social phobia. Being shy results in an increased probability of meeting criteria for social phobia, although the conditions are not completely overlapping. A second key finding is that social phobia is not merely “severe” shyness. A third key finding is that shyness is associated with an increased risk for other forms of psychopathology rather than specifically for social phobia. Finally, a fourth key finding is that introversion is specifically related to social phobia but not other Axis I disorders. The factors accounting for the relationship of shyness to social phobia and other psychopathological states cannot be answered by the findings reported here. However, these findings have raised a number of questions and can be used to generate a number of specific hypotheses that are in need of study.

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Acknowledgements This study was based on a Masters Thesis by the first author under the direction of the second author. The findings were presented in part at the Anxiety Disorders Association of America conference in Washington, DC, March 2000. The study was supported in part by NIMH grant number MH53703 to the second and third authors. The authors would like to thank Karen Jaffe, Amanda Ziegert, Kari Tervo, and Megan Radek for their assistance.

References Andrews, G., & Peters, L. (1998). The CIDI-Auto: A computerised diagnostic interview for psychiatry, discussion paper. Sydney, Australia: World Health Organization. Beidel, D. C., & Turner, S. M. (1998). Shy children, phobic adults: Nature and treatment of social phobia. Washington, DC: American Psychological Association. Beidel, D. C., & Turner, S. M. (1999). The natural course of shyness and related syndromes. In L. A. Schmidt, & J. S. Schulkin (Eds.), Extreme fear, shyness, and social phobia: Origins, biological mechanisms, and clinical outcomes (pp. 203–223). New York: Oxford University Press. Blanchard, J. J., & Brown, S. B. (1998). Structured diagnostic interview schedules. In C. R. Reynolds (Ed.), Assessment (pp. 97–103). Comprehensive clinical psychology, vol. 4. Oxford: Pergamon/Elsevier Science Ltd. Bruch, M. A., Giordano, S., & Pearl, L. (1986). Differences between fearful and self-conscious shy subtypes in background and current adjustment. Journal of Research in Personality, 20, 172–186. Buss, A. H. (1985). A theory of shyness. In W. H. Jones, J. M. Cheek, & S. R. Briggs (Eds.), Shyness: Perspectives on research and treatment (pp. 39–46). New York: Plenum Press. Carducci, B. J. (1999). Shyness: A bold new approach. New York: HarperCollins Publisher, Inc. Carducci, B. J., & Zimbardo, P. G. (1995). Are you shy? Psychology Today, 28, 34–46. Cheek, J. M. (1983). The Revised Cheek and Buss Shyness Scale (RCBS). Unpublished, Wellesley College, Wellesley, MA. World Health Organization (1993). Composite International Diagnostic Interview—version 1.1. Geneva: World Health Organization. Crozier, R. (1979). Shyness as anxious self-preoccupation. Psychological Reports, 44, 959–962. American Psychiatric Association (1994). Diagnostic and statistical manual of mental disorders (4th ed.). Washington, DC: American Psychiatric Association. Di Nardo, P. A., Brown, T. A., & Barlow, D. H. (1995). Anxiety Disorders Interview Schedule for DSM-IV (Lifetime Version). San Antonio, TX: Psychological Corporation. Duggan, C., Sham, P., Lee, A., Minne, C., & Murray, R. (1995). Neuroticism: a vulnerability marker for depression: evidence from a family study. Journal of Affective Disorders, 35, 139–143. Eysenck, H. J., & Eysenck, S. B. G. (1968). Eysenck Personality Inventory, manual. San Diego, CA: Educational and Industrial Testing Service. Heckelman, L. R., & Schneier, F. R. (1995). Diagnostic issues. In R. G. Heimberg, M. R. Liebowitz, D. A. Hope, & F. R. Schneier (Eds.), Social phobia: Diagnosis, assessment, and treatment (pp. 3–20). New York: Guilford Press. Henderson, L., & Zimbardo, P. (1998). Shyness. In Encyclopedia of Mental Health. San Diego, CA: Academic Press. Hurt, S. W., Hyler, S. E., Frances, A., Clarkin, J. F., & Brent, R. (1984). Assessing borderline personality disorder: clinical interview versus self-report versus structured interview. American Journal of Psychiatry, 141, 1228–1231. Hyler, S. E. (1998). Personality Diagnostic Questionnaire. Unpublished, New York State Psychiatric Institute, New York. Hyler, S. E., Rieder, R. O., Williams, J. B., Spitzer, R. L., Lyons, M., & Hendler, J. (1989). A comparison of clinical and self-report diagnoses of DSM-III personality disorders in 552 patients. Comprehensive Psychiatry, 30, 170–178. Hyler, S. E., Skodol, A. E., Kellman, H. D., Oldham, J. M., & Rosnick, L. (1990). Validity of the Personality Diagnostic

N.A. Heiser et al. / Behaviour Research and Therapy 41 (2003) 209–221

221

Questionnaire—Revised: comparison with two structured interviews. American Journal of Psychiatry, 147, 1043– 1048. Jones, W. H., Briggs, S. R., & Smith, T. G. (1986). Shyness: conceptualization and measurement. Journal of Personality Social Psychology, 51, 629–639. Kessler, R. C., McGonagle, K. A., Zhao, S., Nelson, C. B., Hughes, M., Eshelman, S., Wittchen, H., & Kendler, K. S. (1994). Lifetime and 12-month prevalence of DSM-III-R psychiatric disorders in the United States. Archives of General Psychiatry, 51, 8–19. Lazarus, P. (1982). Incidence of shyness in elementary-school age children. Psychological Reports, 51, 904–906. Leary, M. (1991). Social anxiety, shyness, and related constructs. In J. P. Robinson, P. R. Shaver, & L. S. Wrightsman (Eds.), Measures of personality and social psychological attitudes (pp. 161–194). San Diego, CA: Academic Press, Inc. Marshall, J. R., & Lipsett, S. (1994). Social phobia: From shyness to stage fright. New York: Basicbooks. Peters, L., & Andrews, G. (1995). A procedural validity study of the computerised version of the Composite International Diagnostic Interview. Psychological Medicine, 25, 1269–1280. Rapee, R. M. (1998). Overcoming shyness and social phobia: A step-by-step guide. Northvale, NJ: Jason Aronson. Schneier, F. R., Johnson, J., Hornig, C. D., Liebowitz, M. R., & Weissman, M. M. (1992). Social phobia: comorbidity and morbidity in an epidemiologic sample. Archives of General Psychiatry, 49, 282–288. Stemberger, R. T., Turner, S. M., Beidel, D. C., & Calhoun, K. S. (1995). Social phobia: an analysis of possible developmental factors. Journal of Abnormal Psychology, 104, 526–531. Turner, S. M., & Beidel, D. C. (1989). Social phobia: clinical syndrome, diagnosis and comorbidity. Clinical Psychology Review, 9, 3–18. Turner, S. M., Beidel, D. C., & Townsley, R. M. (1990). Social phobia: relationship to shyness. Behaviour Research and Therapy, 28, 497–505. Turner, S. M., Beidel, D. C., & Townsley, R. M. (1992). Social phobia: a comparison of specific and generalized subtypes and avoidant personality disorder. Journal of Abnormal Psychology, 101, 326–331. Wittchen, H. U. (1994). Reliability and validity studies of the WHO-Composite International Diagnostic Interview (CIDI): a critical review. Journal of Psychiatric Research, 28, 57–84. Zimbardo, P. G. (1977). Shyness: What it is, what to do about it. Reading, MA: Addison-Wesley. Zimbardo, P. G., Pilkonis, P. S., & Norwood, R. M. (1975). The social disease called shyness. Psychology Today, 8, 68–72.