خوشه های اختلال تغذیه ای خاص بر اساس اضطراب اجتماعی و جستجوی اخبار

While social avoidance and distress (SAD), a key aspect of social phobia related to behavioral inhibition, is high in different eating disorders (EDs), novelty seeking (NS) is mainly linked to bulimic disorders. Since heterogeneity in NS levels (low/high) exists in social phobia and in about 55% of ED with a highly disturbed personality, we examined ED types based on SAD and NS and their relationships to eating and comorbid features. Scores of 825 ED women on SAD and NS were submitted to cluster analysis. Five clinically differentiated ED clusters emerged: two without SAD (45%) and three with high SAD and low (13%), mid (34%), high NS (8%) levels. High vs. low SAD groups showed greater eating and social impairment, ineffectiveness, ascetism, suicide attempts, and lower education. Among SAD clusters, “SAD–low NS” had the lowest rate of binge eating, vomit, substance use, stealing and compulsive buying, whereas “SAD–high NS” presented the opposite pattern. However, no differences across SAD clusters were found with regard to ED diagnostic category distribution or history of treatment. Findings show that SAD-ED types present heterogeneity of NS and greater severity.

Among anxiety disorders, social phobia frequently overlaps with eating disorders (EDs). Social phobia appears to be the second most common comorbid diagnosis (about 20%) (Kaye, Bulik, Thornton, Barbarich, & Masters, 2004) and the most common comorbid lifetime diagnosis (55–59%) (Godart, Flament, Lecrubier, & Jeammet, 2000). These data, together with evidence regarding social phobia's earlier onset than ED in most cases, as well as of the absence of significant differences in the prevalence of social phobia across ED diagnostic categories (DSM; American Psychiatric Association (APA), 2000) (Godart et al., 2000 and Kaye et al., 2004), led researchers to suggest that social anxiety might be a vulnerability factor for development of any ED (Kaye, 2008 and Schwalberg et al., 1992). However, little is known about how social anxiety as a dimensional trait may link to ED symptoms and related features. Research has identified three personality subtypes in adult patients with eating disorders: high functioning (42–45%), over-controlled and under-controlled. The latter two are characterized by greater comorbidity, poorer social functioning and outcome (Thompson-Brenner and Westen, 2005 and Westen and Harnden-Fischer, 2001). Furthermore, the under-controlled personality type shows high comorbidity of disorders characterized by high social avoidance and distress (Heimberg, Hope, Rapee, & Bruch, 1988). For example, this type has shown higher rates of all anxiety and cluster C personality disorders than the high functioning type. Furthermore, it has even presented higher rates of dependent personality, panic and post-traumatic stress disorder than the over-controlled (Thompson-Brenner & Westen, 2005). Considering both that social anxiety is high and common in all ED types (Kaye et al., 2004) and the high degree of heterogeneity that characterizes ED diagnostic types (Peñas-Lledó et al., 2009), it is likely that both the over- and under-controlled personality prototypes may exist in ED with high social anxiety as has been shown in patients with social phobia (Kashdan et al., 2008, Kashdan and Hofmann, 2008 and Kashdan et al., 2009) These prototypes are also likely to present specific relationships to eating and comorbid symptoms, which are characterized by higher psychiatric severity and poorer functioning. Social anxiety is defined as the strong fear and distress accompanied by avoidance of social situations in which a person might be exposed to negative evaluation by others. Research suggests that social avoidance and distress (SAD) exists on a continuum referred to as the social anxiety spectrum that ranges from the absence of social fear to intense and functionally impairing levels that may include social phobia diagnostic criteria (DSM; APA, 2000) ( McNeil, 2001). This is consistent with recent epidemiological studies showing that, increasingly, social fears are associated with severe manifestations of the disorder (i.e., psychiatric comorbidity, suicide attempts, lower levels of social function and education) ( McNeil, 2001 and Ruscio et al., 2008). In addition, it is well established that an important feature and risk factor of social anxiety and other anxiety disorders is the temperamental trait of harm avoidance (Hayward, Killen, Kraemer, & Taylor, 1998Kaye et al., 2004 and Turner et al., 1996). Harm avoidance has been also associated with vulnerability to ED (Klump et al., 2004), as well as with vulnerability to ED and other comorbid anxiety disorders (Kaye et al., 2004). Individuals with SAD consider that since they are socially inadequate, others will judge them negatively. Thus, they generally use behavioral inhibition and avoidance to suppress negative emotions whenever they cope with social threat cues such as rejection, punishment and novel stimuli. However, despite the fact that behavioral inhibition and avoidance may be effective in suppressing expression of emotions, it may impair regulation of the negative experience associated with them, thereby increasing feelings of worthlessness and inducing impulsive reactions (Gross and John, 2003 and Vohs et al., 2005). In relation to this, novelty seeking (NS), a qualitatively opposed temperamental trait to harm avoidance, has been found to characterize a percent of socially anxious individuals in independent cluster analytic studies (Kashdan et al., 2008, Kashdan et al., 2009 and Kashdan and Hofmann, 2008). Such studies have shown this group of socially anxious individuals with high NS vs. the group with low NS to be characterized by greater use of impulsive behaviors such as substance abuse and greater social impairment. However, these impulsive socially anxious individuals were not found to be more likely to seek treatment for social phobia than other socially anxious individuals ( Kashdan et al., 2009). Considering the high lifetime prevalence of social phobia among ED patients ( Kaye et al., 2004) and that NS is a shared risk factor with anxiety and bulimia nervosa (BN), an eating disorder mostly characterized by the presence of recurrent binge eating and compensatory behaviors ( Wade, Bulik, Prescott, & Kendler, 2004), a subset of ED women may be expected to present high scores on SAD and NS. Further support for this expectation comes from studies of ED patients in which NS explained the confluence of BN and lifetime impulse control disorders ( Fernández-Aranda et al., 2006 and Fernández-Aranda et al., 2008). On the basis of the research described above, we expected to identify at least three clinically relevant groups of ED patients based on SAD and NS: one with low SAD levels, and the other two with high SAD levels in conjunction with low or high NS, respectively. We expected the latter to present the largest number of women with impulsive problems, including bulimic behaviors. Therefore, the aim of the present study was threefold: first, to find clinically relevant and specific eating disorder clusters based on the dimensions of SAD and NS; secondly, to examine their specific relationships to eating and comorbid symptoms; and finally, to explore the distribution of ED DSM diagnoses across the empirical clusters.

The current study provides preliminary data on ED empirical clusters based on social anxiety and novelty seeking. Results appear to be largely consistent with previous cluster analytic or epidemiological studies on social phobia and ED, demonstrating that social anxiety in ED is high at assessment in a population seeking treatment, increases psychopathology and social dysfunction, and involves heterogeneity in bulimic and other impulsive behaviors. It also shows that despite greater severity in the clusters of socially anxious ED women, particularly in the very high impulsive subset, this seems to present no differences with regard to previous number of treatments or perceived need to receive treatment. Finally, it also shows that these “SAD” clusters had no differences in the distribution of ED diagnostic types. These findings may shed light on ED phenomenology, etiology and treatment at cognitive, emotional, behavioral, interpersonal and biological levels. For example, for treatment benefits when exploring SAD in ED, it is also essential to look at NS levels, in order to focus on the motivation behind engaging in internalizing–externalizing impulsive behaviors. It is important to favor those impulsive behaviors that may be functional, because they lead to positive experiences in order to ultimately prevent reinforcing avoidance. Therefore, present results can be useful in future examinations of behavioral and neurobiological processes associated with SAD in ED, and response to particular treatments.