کمرویی، جامعه پذیری، و مشکلات تغذیه ای در نمونه غیر بالینی از دانشجویان دختر

Previous empirical studies have shown that the personality trait of shyness, either alone or in combination with varying levels of sociability (i.e., a socially-conflicted profile—high shyness with high sociability) to be a reliable predictor of various psychopathologies, including substance abuse and mood disorders. Extending these findings to other forms of dysregulated behaviours, we examined multiple measures of eating problems in relation to self-reported shyness and sociability in a sample of 520 undergraduate females (M = 20.7 years). Analyses revealed a consistent significant main effect for shyness across all measures of disordered eating. These findings extend earlier work on shyness to another form of psychopathology (i.e., eating problems) not previously examined in a non-clinical sample.

Shyness, the discomfort and/or inhibition experienced in interpersonal situations, is a personality trait that has been empirically shown over the past several decades to be a reliable predictor of both poor physical and mental health among children and adolescents (Hirshfield et al., 1992, Kagan et al., 1987, Kagan et al., 1988 and Page, 1990), young adults (Bell et al., 1990, Reznick et al., 1992 and Schmidt and Fox, 1995), and even the elderly (Bell et al., 1993). Among adults, a number of psychiatric disorders are correlated with shyness, including anxiety disorders (e.g., social phobia), mood disorders (e.g., depression), and personality disorders (e.g., avoidant personality disorder; Biedel and Turner, 1999, Cox et al., 2005 and Heiser et al., 2003). More recent evidence suggests that there is an advantage to considering the interaction of personality traits in understanding psychopathology. For example, some have argued that a combination of the traits shyness and sociability might help to explain antisocial and problem behaviour in children (Schmidt, 2003), adolescents (Page, 1990), and young adults (Santesso, Schmidt, & Fox, 2004) in addition to the trait of shyness or sociability alone. Specifically, these studies have noted that individuals who are classified as high on both shyness and sociability are more likely to engage in risky behaviours such as substance use and abuse, and to experience problems with social adjustment. Shyness and sociability are known to be orthogonal personality traits in normal (Bruch et al., 1989 and Cheek and Buss, 1981) and atypical (Jetha, Schmidt, & Goldberg, 2007) populations and each of these traits has distinct behavioural (Cheek & Buss, 1981) and psychophysiological correlates (Schmidt, 1999 and Schmidt and Fox, 1994). The notion that shyness and sociability are orthogonal traits was first discussed by Cheek and Buss (1981), who noted that some people withdraw from social situations for different reasons. Cheek and Buss argued that some people may withdraw because they are anxious in social situations (i.e., shy) and others may withdraw because they prefer to be alone (i.e., introverted). After describing on a conceptual level that being high on shyness is not the same as being low on sociability, they then sought to prove that the two dimensions were orthogonal at an empirical level by developing measures to index the two traits. Cheek and Buss first created brief self-report measures to index shyness and sociability separately. They found that both shyness and sociability were only modestly related (r = − .30), suggesting that the two traits were orthogonal. Cheek and Buss then had undergraduates selected for high and low shyness and sociability interact in unfamiliar dyads. The high-shy/high-social group displayed more anxiety during the interaction than undergraduates in the other three groups. Schmidt, 1999 and Schmidt, 2003 has argued that the origins of the shy and social personality style may be linked to underlying differences in approach–avoidance tendencies, resulting in a predisposition to psychological conflict in social situations or anticipation of such situations. Engagement in antisocial and problem behaviours in shy and social individuals may be the result of failed attempts to cope with their stress. Individuals who are both anxious and sociable, are defined by Schmidt as “socially-conflicted”. Shy and sociable people exhibit higher overall frontal activation in both the left and right frontal lobes measured using resting EEG recordings (Schmidt, 1999) and were distinguishable from high shy and low sociable people who exhibited less left frontal EEG activity. This pattern of resting frontal activation may reflect a predisposition toward an approach–avoidance conflict elicited during social interaction or anticipation of social interaction. Schmidt and his colleagues have subsequently argued that the socially-conflicted style may reflect less lateralization of psychological processes (Spere, Schmidt, Riniolo, & Fox, 2005). While intuitively contradictory, the socially-conflicted person is characterized by a strong desire to be social and interact in a variety of social settings, yet their shyness make social interactions uncomfortable and anxiety provoking. The experience of anxiety leads to withdrawal from social situations, or for some, maladaptive coping mechanisms such as abuse of alcohol and other drugs to ease the experience of social interactions. For instance, Page (1990) reports that shy adolescent males use drugs and alcohol as a coping mechanism during anxiety-prone social interactions. The socially-conflicted personality may also exist with a greater propensity among certain subtypes of eating disorders, such as anorexia nervosa binge/purge subtype and bulimia nervosa purging subtype, due to the greater difficulty with impulse regulation, sensation-seeking and risk-taking behaviors among both the socially-conflicted (see Santesso et al., 2004, for example) and among individuals with eating disorders characterized by bingeing and purging (see Cassin & von Ranson, 2005). While no studies to date have investigated the relation between social-conflictedness and eating problems, previous research has shown a link between the construct shyness (although not sociability) and eating pathology in clinical samples (Bulik et al., 1999, Bulik et al., 1995, Fairburn et al., 1997, Lehoux et al., 2000, Slopien et al., 2004, Troop and Bifulco, 2002, Vitousek and Manke, 1994 and Youssef et al., 2004). Importantly, many of these previous studies examined and measured shyness through the related concept “harm avoidance” (Klump et al., 2004), which is a dimension of temperament assessed through Cloninger's Temperament and Character Inventory (Cloninger, Przybeck, Svrakic, & Wetzel, 1994), and is characterized by extreme shyness, fearfulness, and doubt (Klump et al., 2004). Thus, studies explicitly measuring “shyness” in the eating disorders are still needed. Since shyness is an important personality variable in clinical syndromes of eating disorders, we hypothesized that non-clinical women demonstrating elevated levels of disordered eating may also exhibit shyness, as some research has suggested a genetic endophenotype associated with the vulnerability to disordered eating (Bachner-Melman, Zohar, & Ebstein, 2006). Although some personality traits, such as impulsivity, have been shown to appear concurrent with eating disorders and remit upon remission of behavioural symptomology (Bachner-Melman et al., 2006 and Cassin and von Ranson, 2005), other personality traits have been shown to exist prior to the onset of eating disorder illnesses and to persist following recovery (Sullivan et al., 1998 and Klump et al., 2004). If personality traits of clinical interest can be observed in a population-based sample or in a high-risk-sample, this would suggest that these characteristics exist prior to illness onset. Ideally research should examine at-risk samples using a prospective research design, however preliminary evidence of personality vulnerabilities among individuals with disordered eating using cross-sectional research is useful in identifying personality traits of clinical interest. To test this hypothesis, we examined the interaction of shyness with sociability in a large non-clinical sample of university women, a group at high-risk for disordered eating. University and college students may be at higher risk for disordered eating behaviours due to the stress associated with the transition from home to college (see Taylor et al., 2006) as well as the fact that eating disorders are most prevalent in the 15 to 19 age group (APA, 1994). Although the present study appears to be the first to investigate the impact of shyness on eating problems in a non-clinical sample of university women, as well as the first study to examine the interaction of the personality variables shyness and sociability in accounting for unique variance in disordered eating, Miller, Schmidt, Vaillancourt, McDougall, and Laliberté (2006) recently reported an interaction of neuroticism and introversion in predicting disordered eating in a sample of first-year female university students living in campus residences (N = 196). Although recognized as a distinct construct, neuroticism shares some conceptual and empirical overlap with shyness and both seem to be related to a variety of psychopathologies ( Cox et al., 2005). Both Heiser et al. (2003) and Schmidt and Fox (1995) found that individuals with extreme shyness scored significantly higher on measures of neuroticism than less shy individuals in non-patient populations. Still, shyness and neuroticism are distinct in that shyness seems to represent a broader and more heterogeneous personality trait, one that is not consistently association with psychopathology ( Heiser et al., 2003). Neuroticism, however, denotes an enduring tendency to experience negative emotionality and distress ( Cox et al., 2005). Therefore, while preliminary research supports the role of neuroticism in relation to disordered eating in a non-clinical population, it remains unclear how shyness is related to problem eating and more specifically, how the interaction of shyness and sociability may contribute to elevated levels of problem eating. To summarize, the purpose of this study was to 1) extend prior research on shyness and sociability by examining whether the socially-conflicted personality style might also explain disordered eating in a non-clinical sample of young women and 2) to examine the role of shyness in a non-clinical sample of women scoring high on measures of disordered eating. Based on the literature reviewed herein, we predicted a significant main effect for shyness, with high shyness related to high levels of disordered eating. We also predicted a significant shyness by sociability interaction, with high shyness and high sociability related to high levels of disordered eating compared with other levels of shyness and sociability.