Delusionality of body image beliefs in eating disorders

Abstract

Preoccupation with body shape and weight is characteristic of both anorexia nervosa and bulimia nervosa. Despite their diagnostic and clinical significance, evidence on the nature of the underlying beliefs is relatively scarce. We used the Brown Assessment of Beliefs Scale (BABS) to assess the degree of delusionality of body image beliefs in seventy-two participants: 39 with anorexia and 33 with bulimia nervosa. We also investigated the relationship between body image delusionality and other clinical characteristics in eating disorders. Only patients with anorexia nervosa (28.8%) had delusional body image beliefs, whereas overvalued ideas appeared to be frequent in both anorexia and bulimia nervosa. Body image delusionality in anorexia nervosa was associated with restrictive eating pathology, early onset of the disorder and body dissatisfaction, whereas in the bulimia group it was linked to shorter duration of the illness, more intense dieting behaviors and specific psychological factors: ineffectiveness and maturity fears. Results suggest that a delusional variant of anorexia nervosa represents the one end of a continuum of insight among patients with eating disorders. Categorization of patients with eating disorders based on the level of delusionality of body image beliefs could facilitate further research on the role of insight deficits in these disorders.

Introduction

Preoccupation with body shape and weight is characteristic of both Anorexia Nervosa (AN) and Bulimia Nervosa (BN). However, the nature of the underlying beliefs is not clarified by the diagnostic manuals. For instance, the descriptions of body image disturbances in Diagnostic and Statistical Manual of Mental Disorders-4th ed. (DSM-IV) criteria for AN represent a wide range of intensity or persistence of body image beliefs (American Psychiatric Association, 2000), whereas the term ‘intrusive, overvalued idea’ is used in International Classification of Diseases-Tenth Revision (ICD-10) diagnostic criteria (World Health Organization, 1992). Body image beliefs in both AN and BN have been repeatedly considered as overvalued ideas (McKenna, 1984, Fairburn and Cooper, 1989, Vitousek, 1996, Wade and Lowes, 2002), which according to Diagnostic and Statistical Manual of Mental Disorders-4th ed.-Text Revision (DSM-IV-TR) are ‘unreasonable and sustained’ beliefs that are ‘maintained with less than delusional intensity’ (American Psychiatric Association, 2000). Consequently, a degree of conviction ranging between delusional and non-delusional intensity among patients with eating disorders (EDs) is presumed on the basis of clinical observations rather than robust empirical evidence.

In one of the first attempts to define AN, Bruch (1973) described the ‘delusional denial of thinness’ as a core feature of AN and distinguished ‘primary’ AN from the atypical non-delusional form of the illness. In everyday practice, clinicians often describe as delusional AN patients who strongly deny their emaciation. It has been proposed that AN could be classified as ‘with good insight’, ‘with poor insight’ or ‘with psychotic features’ based on the degree of delusionality of body image beliefs (Phillips et al., 1995, van der Zwaard et al., 2006). Insight may be differently defined as awareness of having a mental illness, which might also be impaired in some patients with EDs. For example, patients fulfilling the DSM-IV criteria for AN, except the criterion C about shape and weight concerns, and are thus diagnosed as having an ED not otherwise specified (Becker et al., 2009), might also be unaware of their mental illness (Rieger et al., 2001).

The degree of belief-delusionality in other disorders characterized by irrational thinking, such as obsessive-compulsive disorder (OCD) and body dysmorphic disorder (BDD), can be specified according to DSM-IV, either by the diagnostic specifier ‘with poor insight’ (in OCD) or by the additional diagnosis of delusional disorder (in BDD). Recently, delusionality has been studied through a specific clinical measure, the Brown Assessment of Beliefs Scale (BABS) (Eisen et al., 1998) in OCD (Eisen et al., 2001, Eisen et al., 2004, Ravi Kishore et al., 2004, Alonso et al., 2008, Catapano et al., 2010), BDD (Eisen et al., 2004, Phillips, 2004, Phillips et al., 2006), obsessive-compulsive spectrum disorders (Miguel et al., 2008), and schizophrenia with and without obsessive-compulsive symptoms (Kaplan et al., 2006, Poyurovsky et al., 2007, Faragian et al., 2008). There is, as yet, only a preliminary, small-scale study using BABS to assess delusionality in patients with AN, in which 20% of patients were categorized as delusional. Although a positive association between delusionality and drive for thinness was detected therein, no link between delusionality and any of the overall measures of illness severity was found (Steinglass et al., 2007).

Some noteworthy evidence is derived from studies that assessed denial of the illness or the level of insight in patients with EDs. However, previous studies have reported widely discrepant rates of denial of the illness in AN ranging from 15% to 80%, probably because of inconsistent criteria used to identify patients as denying or insightful (Vitousek et al., 1998): clinical judgement (Halmi, 1974, Fisher et al., 2001), low scores on self-report symptom questionnaires by participants who met diagnostic criteria (Vanderdeycken and Vanderlinden, 1983, Newton et al., 1988, Couturier and Lock, 2006, Viglione et al., 2006), or denial subscales of clinical instruments (Morgan and Russell, 1975, Sunday et al., 1995). A recent study using the Schedule for the Assessment of Insight for EDs, a disorder-specific, multidimensional scale (David, 1990, Kemp and David, 1997), found that 24% of the AN patients, while none of the BN patients, had very low levels of insight and the patients with restricting type AN (AN-R) demonstrated a profile of most severe insight impairment (Konstantakopoulos et al., 2011). In line with this, it was found that AN-R patients had significantly less desire to change their ED-related preoccupations and rituals than both patients with binge-purge type AN (AN-BP) and BN (Sunday et al., 1995). Delusionality of their beliefs about body shape and weight might substantially contribute to unawareness of the illness and lack of motivation for change in patients with EDs.

In the present study we applied for the first time the BABS for the assessment of body image beliefs in AN subtypes and BN. Moreover, we re-evaluated BABS psychometric properties in our ED sample. Based on the findings of previously mentioned studies on insight in EDs, we hypothesized that although both AN and BN patients would exhibit overvalued ideas about body weight and shape, body image beliefs would be delusional only in a subgroup of AN patients. In addition, our hypothesis was that out of all patients with EDs, the patients with AN-R would demonstrate the higher levels of delusionality. Since previous studies in OCD (Ravi Kishore et al., 2004, Alonso et al., 2008, Catapano et al., 2010) and BDD (Eisen et al., 2004, Phillips et al., 2006) have shown a positive relationship between BABS scores and severity of symptoms, we explored the possibility of an association between delusionality and illness severity in both AN and BN.