A phenomenological investigation of overvalued ideas and delusionsin clinical and subclinical anorexia nervosa

Rachel L. Mountjoy a,n, John F. Farhall a, Susan L. Rossell b,c

a School of Psychological Science, La Trobe University, Bundoora, Victoria 3086, Australiab Cognitive Neuropsychology, MAPrc, Monash University Central Clinical School, The Alfred Hospital, 607 St Kilda Road, Prahran, Victoria 3181, Australiac Brain and Psychological Sciences Research Centre, Faculty of Health Sciences, Art and Design, Swinburne University of Technology, P.O. Box 218, Hawthorn,Victoria 3122, Australia

a r t i c l e i n f o

Article history:Received 13 January 2014Received in revised form24 July 2014Accepted 28 July 2014Available online 1 August 2014

Keywords:Body imageEating disordersSchizophrenia

a b s t r a c t

Anorexia Nervosa (AN) is an eating disorder characterised by distorted cognitions about body weight andshape; but little is known about the phenomenological characteristics of these beliefs. In this study,multidimensional and insight-based measurements were used to compare beliefs about body weightand shape in AN to body image dissatisfaction in the general population, and delusional beliefs inschizophrenia. Twenty participants with clinical and sub-clinical AN, 27 participants with schizophreniaand schizoaffective disorder, and 23 healthy controls completed the Brown Assessment of Beliefs Scaleand the Psychotic Symptom Rating Scale in relation to a dominant belief regarding body weight/shape(or body dissatisfaction in healthy controls) or a current delusion. All groups completed the PetersDelusions Inventory to assess the prevalence of a range of delusion-like beliefs. Participants with clinicaland subclinical AN experienced significantly higher preoccupation and distress for their belief incomparison to both participants with schizophrenia/schizoaffective disorder rating a delusional beliefand the healthy controls rating a belief of body dissatisfaction. Both clinical groups were comparable onratings of belief conviction and disruption. The data raise questions regarding the current frameworksthat are used to describe beliefs in AN.

& 2014 Elsevier Ireland Ltd. All rights reserved.

1. Introduction

Anorexia Nervosa (AN) is a chronic eating disorder that is readilyrecognised by significant weight loss and irrational beliefs aboutbody weight and shape. The various symptoms required for adiagnosis of AN fall into three interrelated categories: physical;behavioural; and cognitive (Maguire et al., 2008). The cognitivesymptoms in AN are generally referred to as body image distortion,and are commonly expressed via belief content that the individualis “too fat”, either in reference to the body as a whole, or to specificbody parts. Cognitive-behavioural models have proposed the cog-nitive symptoms of AN as the most pervasive symptoms, and theyplay a more significant role in the development, maintenance andseverity of AN than do the physical or behavioural symptoms(Hetherington, 1993; Mizes and Christiano, 1994; Anderson et al.,2004; Maguire et al., 2008). Beliefs about body weight and shapeare the first symptoms to develop, often present for at least6 months before diagnosis, and are the symptoms most resistantto change (Stewart and Williamson, 2003; Lena et al., 2004).

Despite this recognition, very little is understood about the phe-nomenology of body image beliefs in AN.

The nature of beliefs in AN has been debated, where thesebeliefs have primarily been characterised as overvalued ideas (OI).An OI is defined as an unreasonable and sustained belief that is notobsessional in nature, and is maintained with less than delusionalintensity, meaning the individual can acknowledge that the beliefmight not be true, although insight may nonetheless be poor(Veale, 2002). This description places beliefs in AN on a continuumsomewhere between obsessions with ‘good’ insight and delusionswith ‘no’ insight (Veale, 2002). However, a number of comparisonshave been made of beliefs in AN to obsessions in Obsessive-Compulsive Disorder (OCD), and delusions in psychotic disorders,with findings of some similarities rather than clear differencesbetween these different types of beliefs (Hetherington, 1993;Phillips et al., 1995; Anderson et al., 2004; Powers et al., 2005).Comparisons to obsessions highlight similarities in preoccupationand distress levels (Phillips et al., 1995), while varying proportionsof AN samples have been shown to display at least one delusionalbelief, or a belief with no insight (Grant et al., 2002; Powers et al.,2005; Konstantakopoulos et al., 2012). Early descriptions of ANalso considered an individual's conviction of being fat, despite anobvious state of emaciation, to be a false belief or delusion (Powers

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Psychiatry Research

http://dx.doi.org/10.1016/j.psychres.2014.07.0730165-1781/& 2014 Elsevier Ireland Ltd. All rights reserved.

n Corresponding author. Tel.: þ61 3 9479 1626; fax þ61 3 9479 1956.E-mail address: rlmountjoy@hotmail.com (R.L. Mountjoy).

Psychiatry Research 220 (2014) 507–512

et al., 2005). Efforts to classify beliefs of body image distortion inAN by drawing these comparisons has not yet lead to anyconsensus, with it remaining unclear whether the beliefs in ANare best classified as OIs, obsessions, delusions, or a combination ofthe three (Phillips et al., 1995).

Further efforts to describe beliefs in AN have drawn on researchof another disorder of body image, Body Dysmorphic Disorder(BDD) (Phillips, 2004; Phillips and McElroy, 1993). In the recentlyreleased DSM-5, BDD has specifiers for absent insight and delu-sional beliefs (American Psychiatric Association, 2013). Compar-isons of BDD with and without the presence of delusional beliefshave found few differences in demographic or illness-relatedcharacteristics. These variations are seen as part of the samedisorder with different belief intensity, and a continuum basedon the level of insight has been proposed, where a belief can shiftin either direction along the continuum over time, with improve-ments in insight in response to treatment, or stressors and socialexposure reducing insight, and thus making a belief more delu-sional (Phillips et al., 1994, 1995; Phillips, 2004; Castle et al., 2006;Labuschagne et al., 2010). This model may also have somerelevance to belief intensity in AN and provide an alternativemodel for describing beliefs in AN beyond their definition as OIs(Phillips et al., 1994).

The use of a dimensional approach to describe belief intensityis further supported by the more general debate around thedifficulty in distinguishing the boundary between delusions andOIs, where many have suggested that they are best viewed as lyingon a continuum, rather than being two distinct concepts (Kozakand Foa, 1994; Phillips et al., 1995; Dunne, 2000; Veale, 2002;Yaryura-Tobias, 2004). While insight has been identified as animportant dimension for understanding variations in belief inten-sity, similar research on delusional beliefs in psychotic disordershas adopted a multidimensional framework, rather than relying ona one-dimensional concept such as insight (Phillips et al., 1995).Research into the phenomenology of delusions has explored arange of possible dimensions that could be more broadly adoptedto describe belief intensity. Reviews in this field have highlightedfour consistent dimensions: conviction (how strongly the belief isheld); preoccupation (how often the belief is focused on); distress(whether the belief is linked to negative emotions, such asdepression, anxiety, or anger); and action (whether the belief islinked to certain behaviours) (Garety and Freeman, 1999; Peters,2001; Combs et al., 2006). Of these dimensions, emphasis is givento the degree of conviction to distinguish OIs and delusions, wherea high level of conviction is considered to be the hallmark featureof a delusion, while other dimensions may vary considerably(Oulis et al., 1996; Jones and Watson, 1997).

The use of a multidimensional approach provides the ability toexplore and define belief characteristics in AN via comparison tobeliefs in other disorders. Peters (2001) provides a compellingargument for such comparisons, arguing that the consequences ofa belief (as highlighted by multidimensional assessment) are moreinformative than the content in assessing delusionality. In perhapsthe only study to use a multidimensional approach to comparebelief characteristics in AN with other disorders, Jones and Watson(1997) directly compared beliefs about weight concern in AN andparanoid delusions in schizophrenia. The two groups were foundto differ only on conviction, but not preoccupation, action ordistress. Those with AN had lower levels of conviction, suggestingtheir beliefs were not of delusional intensity and perhaps morefitting the description of an OI. However, the similarities betweengroups on the other dimensions raise the question of whether alldimensions must be significantly different to differentiate OIs fromdelusions. OIs, from a multidimensional perspective, might sharesimilarities across different dimensions to both ‘normal’ anddelusional beliefs, as well as having their own unique qualities,

and may not fall neatly between ‘normal’ and delusional beliefs, asdescriptions based on a single continuum seem to have assumed(Peters, 2001; Peters et al., 2004). Thus, a multidimensionalapproach may be able to broaden our understanding of beliefphenomenology in AN, highlighting those dimensions that holdtrue to the description of OIs, as well as illustrating if similaritiesdo exist with beliefs in other disorders.

In summary, little research has explored the phenomenology ofbeliefs in AN, and research on belief phenomenology in otherdisorders encourages the consideration that beliefs of body imagedistortion can vary on a continuum. Beliefs in AN have tradition-ally been described as OIs, where in a continuum model they willlie between ‘normal’ beliefs in the general population at the lowerend, and delusional beliefs at the upper end. However, multi-dimensional research in other disorders suggests that this will bemost likely for dimensions such as insight and conviction, butprovides little guidance for how other dimensions may rate.

The aim of the current study was to explore the nature andintensity of beliefs of body image distortion in AN, with particularreference to the traditional definition of an OI. The study utilisedboth an insight-based and a multidimensional approach to com-pare body related beliefs in AN, body dissatisfaction in healthycontrols, and delusional beliefs in schizophrenia. It was predictedthat beliefs in AN would show features similar to both OIs anddelusional beliefs.

2. Method

2.1. Participants

The research was approved by the La Trobe University Human Ethics Commit-tee, Melbourne. Three groups were recruited into the study. Informed consent wasobtained after the nature of participation had been fully explained, and capacity forconsent of clinical groups was determined by a treating clinician. The “anorexianervosa (AN)” group comprised 11 inpatient and nine outpatient females with acurrent DSM-IV-TR diagnosis of Anorexia Nervosa or Eating Disorder Not OtherwiseSpecified (EDNOS). The “schizophrenia” group comprised 20 males and sevenfemales with a current DSM-IV-TR diagnosis of Schizophrenia or SchizoaffectiveDisorder who reported currently experiencing one or more delusions and treatedas outpatients. The “control” group comprised 23 female members of the generalpublic with no history of mental illness. The Mini International NeuropsychiatricInterview (MINI; Sheehan et al., 1998) was used to confirm current diagnoses. Allparticipants were between 18 and 55 years of age. Clinical groups were recruitedfrom public and private mental health services in Melbourne. The non-clinicalgroup was recruited from a Melbourne-based university. Exclusion criteria forparticipation involved an IQ below 80 (as scored by the WTAR; The PsychologicalCorporation, 2001), a history of brain injury or neurological disorder, poorconversational English, substance abuse or dependence within the past 12 months,evidence of grossly disorganised thinking or behaviour, or currently requiringmedical intervention or naso-gastric feeding. Gender, age, body mass index (BMI)and education were recorded as demographic variables for all participants.

In the AN group, 7 participants met full criteria for AN (two binge-purge subtype,five restricting subtype), and 13 meet criteria for EDNOS. Those with a diagnosis ofEDNOS had historically received a full diagnoses of AN, and had to currently meet allcriteria for AN with the exclusion of either the weight or menstruation criteria, anddid not meet criteria for Bulimia Nervosa. This was considered a ‘sub-threshold’presentation of AN, which has been shown to have clinical similarities to full-criteriaAN (Grange et al., 2013). At the time of testing, those who met full criteria for AN hada mean BMI of 15.59 (S.D.¼1.70) and those who met EDNOS criteria had a mean BMIof 20.81 (S.D.¼3.18) (BMI differences did not show any relationship to the mainresults). In the schizophrenia sample, 22 participants had a diagnosis of schizo-phrenia and five of schizoaffective disorder. A majority of the AN group self-reportedthey were receiving an antidepressant (85%), and 45% were receiving an antipsy-chotic (all atypicals). All participants in the schizophrenia group reported receivingone or more antipsychotic medications and 30% were receiving one or moreantidepressants (see Supplementary Table A for further details).

2.2. Materials

Brown Assessment of Beliefs Scale (BABS; Eisen et al., 1998): a seven-item,clinician administered, semi-structured interview measuring the degree of insightover the past week for a nominated belief. AN and control group participants were

R.L. Mountjoy et al. / Psychiatry Research 220 (2014) 507–512508

asked to identify a negative belief relating to body weight or shape, or a negativeappearance-related belief. Schizophrenia group participants were asked to discussa current delusional belief. Items are scored on a five-point ordinal scale (0–4), withanchor points provided, and the total score ranges from 0 to 24. The BABS TotalScore and conviction ratings can be utilised to classify beliefs as being delusional, orhaving ‘poor’ or ‘good’ insight (Delusional: conviction¼4, total scoreZ18; PoorInsight: conviction¼3, total scoreZ13; Good Insight: all other scoring combina-tions). A fourth category considered to also represent poor insight was created forthis research: those participants with a conviction of four and a total score in therange of 13 to 17 (inclusive). This category contains elements of both the delusionaland poor insight categories, and was separate to avoid potential skew on the goodinsight category.

Psychotic Symptom Rating Scales – Delusions (PSYRATS: Haddock et al., 1999):a semi-structured interview assessing the subjective characteristics of delusions.Each item is rated on a five-point ordinal scale (0–4), with anchor points provided.Total scores range from 0 to 24, where higher scores represent beliefs of greaterintensity. Participants rated the same belief identified on the BABS.

Peters et al. Delusions Inventory (PDI; Peters et al., 1999): a 21-item self-reportquestionnaire measuring unusual beliefs and vivid mental experiences, and issuggestive of a propensity to delusional thinking. Each item is rated yes/no, toindicate whether it has ever been experienced, and for ‘yes’ responses participantsrate the degree of distress, preoccupation and conviction associated with theendorsed statement on a five-point Likert scale.

2.3. Procedure

Participation took approximately 1 h. Tasks were administered in the orderlisted above for all participants.

3. Results

3.1. Demographic information

Significant group differences were found on the four demo-graphic variables (see Table 1). The schizophrenia group hadsignificantly fewer females, was significantly older, and had sig-nificantly fewer years of education in comparison to the AN andcontrol groups, which were comparable. Years of education rangedbetween 7.0 and 20.5 years, with group means indicating anaverage education level to at least age 16 years. There weresignificant group differences for BMI in the expected direction:The AN group had significantly lower BMI than the other groups:and the control group also had a significantly lower BMI than theschizophrenia group.

3.2. Data screening and analysis

Age and gender differences across and within groups wereexplored using correlations and t-tests. Correlations were con-ducted between age and the six main outcome measures. Sig-nificant correlations were found between age and BABS Total Score(r¼0.43, po0.001), and PDI Total Items Endorsed (r¼0.42,po0.001). Age is used as a covariate in the analysis of groupdifferences for the BABS Total Score. When Age was used as acovariate in an ANCOVA examining group differences on the PDITotal Items Endorsed, the assumption of homogeneity was vio-lated, and the pattern of results was no different from an ANOVA,so the latter results have been reported. t-tests were used to assessgender differences within the schizophrenia group on the six mainoutcome measures. No gender differences were found.

3.3. PSYRATS and BABS

One-way ANOVA on the PSYRATS Total Score and one-wayANCOVA on the BABS Total Score (with age as a covariate)indicated significant group differences on both measures (seeTable 2). Post-hoc analyses (SNK) found the AN group had asignificantly higher total score on the PSYRATS than the othergroups, with the schizophrenia group significantly higher than the

control group. On the BABS Total Score, the AN group did not scoresignificantly different to the control group, but scored significantlylower than the schizophrenia group. The schizophrenia groupagain had a significantly higher total score than the control group(Covariate adjusted means and standard error: AN 12.02, 1.12; SZ15.96, 1.10; HC 9.25, 1.08).

A χ2 test for independence found a significant group differencefor the proportion of participants in each group classified asdelusional by the BABS, χ2 (2, N¼70)¼10.14, p¼0.006, where asignificantly higher proportion of participants in the schizophreniagroup were classified as delusional (see Table 3). Similar percen-tages of participants in the AN and schizophrenia groups wereclassified as having poor insight. In both the AN and controlgroups, the majority displayed good insight into their dominantbelief.

Individual items of the PSYRATS were explored to examine thegroup differences on the various dimensions. Planned compari-sons with Mann–Whitney-U tests were conducted on ordinal data.The planned comparisons utilised were AN – schizophrenia andAN – controls (see Table 4). Given the number of comparisonsmade, the alpha level was adjusted using Bonferroni correction toα¼0.004.

In comparison to both the schizophrenia and control groups,the AN group endorsed significantly higher levels of preoccupationand distress in relation to their dominant belief. Belief convictionwas rated by the AN group similarly to the schizophrenia andcontrol groups. The AN group rated a significantly higher degree oflife disruption from their belief than did the control group, butwere comparable to the schizophrenia group.

Individual items of the BABS were explored to examine thegroup differences on the various dimensions. Planned compari-sons with Mann–Whitney-U tests were conducted on ordinal data.The planned comparisons utilised were AN – schizophrenia, andAN – controls (see Table 5). Given the number of comparisonsmade, the alpha level was adjusted using Bonferroni correction toα¼0.005. The BABS item on Conviction was excluded fromanalysis, as this item is replicated in the PSYRATS.

The AN group was comparable to the schizophrenia group onall items of the BABS, with the exception of the “insight” item,where the AN group was significantly more likely to attributetheir belief to a psychological/psychiatric cause. The anorexiagroup was comparable to the control group on all items ofthe BABS.

3.4. PDI

One-way ANOVAs were used to assess group differences on thePDI (see Table 2). All variables met assumptions for normality andhomogeneity of variance, except for the PDI Total Items Endorsed,which violated the assumption of homogeneity. For this variablethe Welch F-ratio and Games–Howell post-hoc tests are reportedto correct for this violation. Given the small sample size, thesetests were selected as they are more liberal (Field, 2009). All otheranalyses utilised SNK post-hoc tests. For total items endorsed, theAN and schizophrenia groups were comparable, and endorsed agreater number of unusual beliefs than the control group. Ratingsof distress and preoccupation were significantly higher in the ANgroup than the other two groups. The schizophrenia group alsorated significantly higher than the control group on these items.No group differences were found for conviction.

4. Discussion

The results of the current research question the traditionalclassification of beliefs in AN as OIs. On the insight measure, the

R.L. Mountjoy et al. / Psychiatry Research 220 (2014) 507–512 509

AN group mean score was intermediate to that of the control and

schizophrenia groups, but not statistically different to that of thecontrol group, which provides limited support for the classificationof beliefs in AN as OIs, by illustrating better insight for beliefs inAN than for delusions in schizophrenia, but equivalent insight tothat held in the general population. A broad range of insight wasfound for beliefs in AN, ranging from ‘good’ insight, which is betterthan expected for an OI, through to no insight and a ‘delusional’belief in a small subgroup. Analysis of the cut-off scores illustratesthat only 30% of the AN group held a belief with “poor” insight,with the majority displaying “good” insight. Three studies utilisingthe BABS in AN samples have found similar results, where 28%,25.6% and 26% displayed poor insight, with the majority of eachsample having good insight into their belief (Steinglass et al.,2007; Konstantakopoulos et al., 2012; Hartmann et al., 2013).The current study also illustrated that beliefs in AN can be heldwith delusional intensity, finding 10% of the AN group to rate inthis category. Other studies have found higher rates, with 20%,28.2% and 16% of AN samples holding either food-related orbody-related beliefs with delusional intensity (Steinglass et al.,

Table 1Descriptive statistics for demographic variables.

AN (N¼20) SZ (N¼27) HC (N¼23) Contrasts

No. female (%) 20 (100) 7 (35) 23 (100) χ2 (2, N¼70)¼44.59, po0.001 SZoAN¼HCAge (years) 25.55 (7.35) 38.33 (8.81) 24.57 (7.05) F (2, 67)¼23.89, po0.001 AN¼HCoSZEducation (years) 13.98 (2.67) 11.82 (2.68) 14.72 (1.81) F (2, 67)¼9.73, po0.001 SZoAN¼HCBody mass index 18.98 (3.71) 29.40 (5.44) 24.42 (5.61) F (2, 67)¼24.35, po0.001 ANoHCoSZ

Note. Mean (S.D.) for all variables except Gender, which is a frequency count (%).AN¼anorexia, SZ¼schizophrenia, HC¼healthy controls.

Table 2Group means for main outcome measures.

AN (N¼20) SZ (N¼27) HC (N¼23) Contrasts

PSYRATS total score a 17.55 (3.87) 12.93 (3.32) 6.78 (2.95) F (2, 67)¼55.41, po0.001, partial η2 ¼0.62 AN4SZ4HCBABS total score a 11.70 (4.50) 16.52 (5.30) 8.87 (4.33) F (2, 66)¼7.80, p¼0.001, partial η2 ¼0.19 SZ4AN¼HCPDI total items endorsed b 32.14 (19.41) 46.38 (25.49) 12.63 (7.94) F (2, 35.60)¼26.80, po0.001 HCoAN¼SZPDI mean conviction c 3.25 (0.80) 2.90 (0.81) 2.60 (1.10) F (2, 67)¼2.74, p¼0.072, partial η2 ¼0.08 HC¼SZ¼ANPDI mean preoccupation c 3.28 (0.85) 2.72 (0.81) 2.00 (1.07) F (2, 67)¼10.72, po0.001, partial η2 ¼0.34 HCoSZoANPDI mean distress c 3.30 (0.86) 2.48 (0.89) 1.69 (0.93) F (2, 67)¼17.22, po0.001, partial η2 ¼0.24 HCoSZoAN

Note. Values in parentheses represent standard deviations. AN¼anorexia, SZ¼schizophrenia, HC¼healthy controls, PSYRATS ¼ Psychotic Symptom Rating Scale,BABS ¼ Brown Assessment of Belief Scale, PDI¼Peters Delusions Inventory.

a Total score out of 24.b Mean percentage of items endorsed.c Scores represent Likert-Scale responses from 1 to 5.

Table 3Number of participants displaying delusional and non-delusional beliefs usingBABS criteria.

AN (N¼20) SZ (N¼27) HC (N¼23)

Delusional a 2 (10) 10 (37) 1 (4)Poor insight variation b 0 (0) 5 (19) 1 (4)Poor insight c 6 (30) 7 (26) 1 (4)Good insight d 12 (60) 5 (19) 20 (87)

Note. Values in parentheses represent percentages. AN¼anorexia, SZ¼schizophre-nia, HC¼healthy controls.

a Conviction¼4, BABS Total score418.b Conviction¼4, BABS Total score 13–17 (inclusive).c Conviction¼3, BABS Total score413.d All other scoring combinations.

Table 4Median scores of the PSYRATS individual items.

U z p

AN – SZ comparison AN SZAmount preoccupation 3.00 2.00 119.50 �3.42 0.001Duration preoccupation 3.00 2.00 92.50 �4.08 0.000Conviction 3.00 4.00 178.50 �2.16 0.031Amount of distress 3.00 2.00 125.00 �3.32 0.001Intensity of distress 3.00 1.00 111.50 �3.56 0.000Disruption 3.00 2.00 177.00 �2.11 0.035

AN-HC Comparison AN HCAmount preoccupation 3.00 1.00 36.00 �4.86 0.000Duration preoccupation 3.00 1.00 25.00 �5.15 0.000Conviction 3.00 3.00 163.50 �1.82 0.069Amount of distress 3.00 1.00 33.50 �4.91 0.000Intensity of distress 3.00 1.00 33.00 �4.97 0.000Disruption 3.00 0.00 3.00 �5.97 0.000

Note. p-values in bold remained significant after Bonferroni correction (α¼0.004).AN¼anorexia, SZ¼schizophrenia, HC¼healthy controls. PSYTRATS¼PsychoticSymptom Rating Scale.

Table 5Median scores of the BABS individual items.

U z p

AN – SZ comparison AN SZPerception of others views 1.00 2.00 164.00 �2.36 0.018Differing views 2.50 3.00 179.00 �2.05 0.040Fixity 2.50 3.00 211.50 �1.31 0.191Attempt to disprove 3.00 4.00 175.50 �2.14 0.032Insight 0.00 2.00 94.50 �3.89 0.000

AN-HC Comparison AN HCPerception of others views 1.00 1.00 188.00 �1.11 0.265Differing views 2.50 1.00 176.00 �1.36 0.174Fixity 2.50 2.00 131.00 �2.53 0.012Attempt to disprove 3.00 2.00 153.00 �1.94 0.053Insight 0.00 0.00 160.50 �2.09 0.037

Note. p-values in bold remained significant after Bonferroni correction (α¼0.005).AN¼anorexia, SZ¼schizophrenia, HC¼healthy controls. BABS¼Brown Assessmentof Belief Scale.

R.L. Mountjoy et al. / Psychiatry Research 220 (2014) 507–512510

2007; Konstantakopoulos et al., 2012; Hartmann et al., 2013). Thus,beliefs in AN can be seen to have a broader range of insight thatthe “poor” insight of an OI.

The multidimensional assessment highlighted several phenomen-ological similarities between the AN and schizophrenia groups. Bodyimage distortion in AN and delusions in schizophrenia were similar inratings of both conviction and disruption. The similarity in beliefconviction is significant, given that conviction is typically seen as thedefining feature of a delusion (Garety and Hemsley, 1987; Oulis et al.,1996). This raises the question of what other belief characteristics arerequired for a belief to reach the “severity” of a delusion, if convictionalone is not an indicator of this. Indeed, body image beliefs in ANshowed higher ratings of preoccupation and distress than delusions inschizophrenia. This pattern of results was further supported by similarratings on the PDI, where conviction ratings were found to be similaracross groups, with distress and preoccupation rating highest in theAN group. Similar results have also been found in research using thePDI in BDD, where conviction levels were similar to control groups,but distress and preoccupation were higher (Labuschagne et al., 2010).

Results from the PSYRATS found the AN group to experience morefrequent and more intense distress relating to their beliefs, as well ashigher preoccupation, in terms of both thinking about their beliefmore times during the course of a week, and for significantly longerdurations when the belief did arise. One possible explanation of theseresults in the AN group is that levels of preoccupation and distressmay be related to level of insight. The individual item analysis of theBABS suggests that the main component of insight related to clinicalgroup differences was whether or not the beliefs were seen to have apsychological or psychiatric origin, where participants with AN weremore able to connect their belief with their diagnosis. A greaterawareness of this connection, where holding a certain belief is seen asa ‘bad’ thing or something that should not be thought, couldpotentially serve to increase distress levels and preoccupation asindividuals start to “struggle” with their belief. This relationship couldhave implications for treatment in AN, as while good insight is animportant element of treatment, high levels of distress and preoccu-pation may limit an individual's ability to engage in more complexdiscussion or therapy, and interventions targeted at these dimensionsmight be required.

A major limitation of the current study is the small sample sizesused, thus results should be considered preliminary and will needreplication in larger samples. Future research will also need toexamine more heterogeneous groups, as results may have beeninfluenced by sex and age differences in the schizophrenia group,and diagnostic differences within the two clinical groups. Age sub-groups will be especially important to consider, as body imageattitudes may vary across the lifespan. Another limitation is that manyparticipants in the AN group were inpatients, whereas participants inthe schizophrenia group were all outpatients. The higher level of carein the AN group is an alternative hypothesis for their higher thanexpected levels of preoccupation and distress. AN ratings of goodinsight may also reflect a sampling bias, where those with betterinsight are more likely to engage in research programs and be willingto discuss their belief. This group may also show a higher degree ofsocial desirability in their responding (which should be assessed infuture research). However, the acceptance of inpatient admission andtreatment may reflect better levels of insight, and community sampleswith AN may indeed show poorer insight than that reflected in thecurrent study. The use of antipsychotics by almost half of the AN groupmay also improve the degree of reported insight, but may also reducethe levels of preoccupation and distress experienced, and futureresearch will need to consider controlling for medication use, whichwas not possible in the current study.

The current results highlight several areas for future research. Thepresence of delusional beliefs in AN is one such area, given both thecurrent research and other studies have found a subgroup of those

with AN can hold beliefs with delusional intensity (or no insight). Theexploration of delusional beliefs in AN, while diagnostically intriguing,may have more important clinical implications, for example toestablish if delusional beliefs in AN correlate with poorer treatmentoutcomes, as is the case with BDD (Phillips et al., 1994, 1995; Phillips,2004) or if this varies with AN subtype (Konstantakopoulos et al.,2012). Hartmann et al. (2013) suggest the adaptation of therapystrategies currently used to address delusional beliefs in BDD maybe warranted in the treatment of AN where delusional beliefs arepresent. Further investigation of belief phenomenology in AN isrequired, along with consideration of the diagnostic implications forthis disorder. The diagnostic framework used for BDD might provemore suitable for describing the presentation of AN in the future. Thesimilarities of beliefs in AN with several dimensions of delusionssuggests that a subgroup of individuals with AN could be described ashaving a non-bizarre delusion. Powers et al. (2005) have indeedproposed that diagnostic criteria for AN could include the specifier‘With Psychotic Features’, to indicate the individual has a delu-sional belief around themes of body weight and shape. AlsoKonstantakopoulos et al. (2012) suggest that a delusional variant ofAN may exist at one extreme of a continuum of insight.

While the classification of beliefs of body image distortion asOIs appears to be fitting in some cases, it does not adequatelydescribe the full range of belief intensity in the disorder. Theresults highlight that beliefs in the two clinical populations mightbe more similar in presentation than traditional definitions of OIsand delusions suggest, and describing beliefs on a continuum is animportant method to capture the true range of experiences thatdiscrete classifications of beliefs does not allow. While pastdefinitions of delusional beliefs have been based around thedegree of insight, a multidimensional perspective may havegreater utility for describing the overall phenomenology andseverity of AN.

Acknowledgement

The authors have no conflicts of interest to report.Rachel Mountjoy was supported by a La Trobe University

Postgraduate Research Scholarship.

Appendix A. Supporting information

Supplementary data associated with this paper can be foundin the online version at http://dx.doi.org/10.1016/j.psychres.2014.07.073.

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