The clinician administered staging instrument for anorexia nervosa: Development and psychometric properties

The Clinician Administered Staging Instrumentfor Anorexia Nervosa: Development and

Psychometric Properties

Sarah Maguire, PhD1*Stephen Touyz, PhD1

Lois Surgenor, PhD2

Ross D. Crosby, PhD3

Scott G. Engel, PhD3

Hubert Lacey, MD4

Suzanne Heywood-Everett,DClinPsy5,6

Daniel Le Grange, PhD7

ABSTRACT

Objective: To develop and evaluate an

instrument to assess severity in anorexia

nervosa (AN), the Clinician Administered

Staging Instrument for Anorexia Nervosa

(CASIAN).

Method: Candidate items for the CASIAN

were developed in three phases (domain,

content, and item generation) followed by

a pilot study. The psychometric properties

of the resultant 34-item questionnaire

were investigated in cross-sectional and

longitudinal samples (N 5 171) with DSM-

IV AN and subthreshold AN.

Results: Item and factor analysis proce-

dures resulted in a refined 23-item

CASIAN comprising of six factors (‘‘Moti-

vation,’’ ‘‘Weight,’’ ‘‘Illness Duration,’’

‘‘Obsessionality,’’ ‘‘Bulimic Behaviors,’’

and ‘‘Acute Issues’’). The CASIAN had high

internal consistency (.811), test–retest

(.957), and interrater reliability (.973).

Preliminary support for the convergent,

discriminant, concurrent, and predictive

validity of the CASIAN was found.

Discussion: The CASIAN is a psychomet-

rically sound instrument. Further studies

are needed to confirm the factor structure

and assess its clinical and research utility.VVC 2011 by Wiley Periodicals, Inc.

Keywords: anorexia nervosa; severity;

stages; staging; assessment; diagnosis;

eating disorders

(Int J Eat Disord 2012; 45:390–399)

Introduction

Anorexia nervosa (AN) has been proposed to existon a continuum of severity, and even the earliestdescriptions of AN suggested stages of severityoccur within the illness. Lasegue,1 for example,described a gradual descent into the illness anddistinguished between three distinct ‘‘phases’’ in itsprogression. Modern day diagnostic practices are

predicated on the construct of severity and draw anarbitrary distinction somewhere along its contin-uum to divide illness from nonillness. Treatmentregimens are often informed by and designed fordiffering levels of severity. Hence a definition of se-verity, a method for conceptualizing the continuumand a tool to assess it in its entirety, becomes animportant endeavor in any disease, including AN.

There are numerous references to levels of illnessseverity in the eating disorders literature.2–9 Indeed, itis widely accepted that the illness spectrum is largerthan those cases eligible for full diagnosis accordingto DSM-IV.10–15 Epidemiological studies alsoacknowledge this and include prevalence and inci-dence rates of both full-syndrome AN and partialAN.11,13,16–19 These studies define partial AN differ-ently: some use an absence of amenorrhoea to desig-nate a partial case,19 others define a subthresholdcase as meeting all but the amenorrhoea or weightcriteria11,18 and still others include cases that meetthe low-weight criteria plus at least one other of thethree remaining DSM-IV diagnostic criteria.13,16,17

Another approach to understanding the spec-trum has been to examine the difference betweenfull and partial cases. A recent latent class analysisattempted to identify clusters of illness withinEDNOS and concluded that most cases resembledthe existing specified categories of AN, BN, and

Supported by MH079979 and MH083914 from NIH and Guilford

Press and Training Institute for Child and Adolescent Eating Disor-

ders, LLC.

*Correspondence to: Sarah Maguire, Centre for Eating and Diet-

ing Disorders, 1-3 Derwent St, Glebe 2037, Australia.

E-mail: [email protected]

Accepted 19 June 2011

1 School of Psychology, University of Sydney, Sydney, Australia2 Department of Psychological Medicine, University of Otago,

Christchurch, New Zealand3 Neuropsychiatric Research Institute, University of North

Dakota School of Medicine and Health Sciences, Fargo, North

Dakota4 St Georges School of Medicine, University of London, London,

United Kingdom5Division of Psychology, Yorkshire Centre for Eating Disorders,

Leeds, United Kingdom6 Bradford District Care Trust, Bradford, United Kingdom7Department of Psychiatry and Behavioral Neurosciences, The

University of Chicago, Chicago, Illinois

Published online 30 August 2011 in Wiley Online Library

(wileyonlinelibrary.com). DOI: 10.1002/eat.20951

VVC 2011 Wiley Periodicals, Inc.

390 International Journal of Eating Disorders 45:3 390–399 2012

REGULAR ARTICLE

BED.20 In short, most EDNOS cases can be concep-tualized as existing on a continuum with full-syn-drome cases. In respect to AN, the majority of stud-ies have demonstrated little difference on the axesassessed between full and partial syndrome.21–24 Arecent meta-analytic review concluded that full-syndrome AN represents the severe end of a con-tinuum, with EDNOS ‘‘lying’’ closer to AN than thecurrent diagnostic conceptualization suggests.24

Many instruments have been designed to assessparticular features of AN, several for the purposes ofscreening and diagnosis, and others to assess treat-ment outcome.25 Because of the absence of a reli-able and validated instrument to assess severity inAN, it has been common for these instruments, ei-ther singly or as part of a battery, to be used inresearch as proxy measures of severity.26,27 Althoughthese proxy measures are likely related to compo-nents of severity, these instruments are typically notvalidated as measures of severity. To our knowledge,only one (partly) validated instrument exists that ex-plicitly attempts to assess overall illness severity.The Short Evaluation of Eating Disorders28 is a rela-tively recently developed self-report questionnairethat assesses three of the four diagnostic criteria forAN rated 0–3 (0 5 not present, 1 5 mild, 2 5 meetsdiagnosis, and 3 5 extreme) with the most impor-tant symptom (i.e., weight loss) counted double. Itderives a total severity index for anorexic symptomsand enables measurement of the diagnostic criteriafor AN. However, as a brief instrument, it does notallow for a comprehensive evaluation of all of theclinical features purported to contribute to severityand relies heavily on the criteria that currently com-prise DSM-IV diagnosis of AN. Studies of its reliabil-ity and discriminant validity are yet to be published.

In summary, despite what appears to be wide-spread assumptions about the importance of sever-ity within the AN, there remains uncertainty aboutprecise definitions and components involved in se-verity. Only limited attempts to develop empiricallysupported measures of this construct have beenmade. The purpose of the current study is to developand test the psychometric properties of a clinician-administered multidimensional measure to assessseverity. Here, we outline its development anddescribe a series of preliminary validation studies.

Method

Item Generation and Pilot Testing

Generation of items for the Clinician Administered

Staging Instrument for Anorexia Nervosa (CASIAN) was

conducted in three primary phases: domain generation,

content generation, and item generation.

Domain generation: Five doctoral level eating disorder

experts (DLG, HL, ST, LS, and PB) identified areas of ill-

ness symptomatology in AN believed to be pertinent to

illness severity. The experts were specifically asked to

consider the full spectrum of psychological, behavioral,

and physical symptomatology of AN from mild through

to severe. Once broad domains were generated, they

were aggregated to remove redundancies and overlap-

ping domains. This step produced seven general domain

areas: weight/weight history, chronicity, dietary control,

compensatory behaviors, psychological status, physical

status, and egosyntonic features.

Content generation: Four experts (DLG, HL, ST, and LS)

as well as the first author generated relevant symptoms to

be assessed within each domain. Next, items designed to

tap each of these content areas were generated. A broad

range of instruments were reviewed for potentially appli-

cable items to be adapted, including the Eating Disorder

Inventory-3,29 the Eating Attitudes Test,30 the Morgan-

Russell Outcome Assessment Schedule,31,32 Rating of Eat-

ing Disorder Severity (REDS; Goldner, E. Rating of Eating

Dsiorder Severity (REDS), Personal Communication), Ano-

rexia Nervosa Stages of Change Questionnaire,33 and the

Eating Disorder Belief Questionnaire.34 A final review by

all five experts led to some items being eliminated, others

revised, and some additions.

This initial version of the CASIAN was then reviewed

by another independent expert panel of five clinicians to

verify that the illness areas had been adequately

addressed. Each member of this panel had a minimum of

10 years experience treating eating disorders. The panel

included two dietitians, two nurses, and one general

practitioner. As a result of this process, the CASIAN was

revised with certain items eliminated, others added, and

others reworded or redesigned.

As is a suggested practice,35 this second draft of the

CASIAN was then subjected to pilot testing. Sixteen pilot

participants (females aged 15–44 years) with AN or

EDNOS-AN subtype attending an eating disorders pro-

gram in Sydney, Australia, were interviewed individually.

The interview comprised the pilot version of the CASIAN

followed by open-ended questions centering on patient

experience of the questionnaire (e.g. ‘‘Can you gauge

what the questionnaire is trying to achieve?,’’ ‘‘Do you

think the range of questions asked address the severity of

your illness?’’). Interviews were digitally recorded.

Results of the pilot testing were analyzed by two of the

four experts from the original panel. CASIAN items were

further added, deleted, or modified through this process.

This final version was distributed to the whole panel for

final comment. This resulted in a 34-item clinician

administered questionnaire assessing a broad range of

AN symptomatology across seven illness domains of

THE CLINICIAN ADMINISTERED STAGING

International Journal of Eating Disorders 45:3 390–399 2012 391

weight history, duration of illness, eating behaviors, com-

pensatory behaviors, psychological status, physical sta-

tus, and illness entrapment (full CASIAN available on

request). As part of item generation and pilot testing, it

was decided that current weight was the most important

factor in the staging model and hence is given double

weighting in item scores, a procedure followed by

others.28

Participant Recruitment

To obtain a sample with a broad range of illness sever-

ity, participants were recruited from five recognized spe-

cialist eating disorder treatment services and affiliated

community service providers in three countries (Royal

Prince Alfred Hospital, Wesley Private Hospital, and the

University of Sydney Counseling Service, all Sydney, Aus-

tralia; The University of Chicago, Chicago, USA; St

Georges Hospital, London, UK; Leeds Eating Disorder

Service, Leeds, UK).

DSM-IV diagnostic criteria were used to identify indi-

viduals, aged 16 years or above, with AN eligible for par-

ticipation. To capture the full spectrum of illness severity,

including those persons in partial recovery or in the early

stages of illness not yet meeting full criteria, individuals

with EDNOS were also included. Ricca et al.14 adjusted

DSM-IV criteria for EDNOS were used to determine eligi-

bility, that is, meeting all criteria for AN except criterion

D [EDNOS-AN(m)] and except criterion A [EDNOS-

AN(w)]. All participants were diagnosed by the primary

clinicians at each site following routine interview and

assessment. The mean age of the total sample (n 5 171,

98% female) was 24.4 years (SD 5 8.1; range 5 16–58),

with a mean body mass index (BMI 5 kg/m2) at baseline

of 16.5 (SD 5 2.3; range 5 9.5–23.6). Mean illness dura-

tion was 7.9 years (SD 5 7.6; range 5 0–38), with 43.3%

meeting full-criteria for AN, and 56.7% EDNOS-AN. Of

the total sample, 23.4% did not meet criterion D and

33.3% did not meet criterion A. Half the sample (50.9%)

were restricting AN and 49.1% were binge/purging

type.36 Information was not collected on the number or

nature of persons who declined to participate in the

study.

The psychometric properties of the CASIAN were eval-

uated in a series of four studies (see below) involving dif-

ferent subgroups of this sample.

Procedure

Participants were initially assessed within 2 weeks of

being admitted to an intensive treatment program (inpa-

tient, day-treatment, or outpatient family-based treat-

ment) for their eating disorder, or at any time during

usual care outpatient treatment. All interviewers were

honors graduates in psychology or above and employed

at the data collection site. All interviewers were trained in

administration of the CASIAN by the first author (SM).

Training involved a half-day workshop, followed by an

initial trial administration of the CASIAN by each inter-

viewer. A video-taped sample CASIAN interview was per-

manently available at each site and was watched by each

interviewer following their first trial administration. The

first test administrations of the CASIAN by each inter-

viewer were either observed by SM and cross-scored or

were taped and cross-scored. As the relevant period of

examination for the CASIAN is the month before assess-

ment, a maximum period of 2 weeks of intensive treat-

ment within the last four was chosen to ensure that an

assessment of the eating disorder was achieved without

coercion.

Other Measures

Other measures and procedures were administered to

particular cohorts of the total recruited sample, depend-

ent on the validation study undertaken (see below).

Eating Attitudes Test (EAT30,37–40;) is a 40-item self-

report measure developed to evaluate a range of eating

behaviors associated with AN.

Mizes Anorectic Cognitions Scale—Revised (MAC-R41)

is a 24-item self-administered questionnaire examining

eating disorder cognitions. The MAC-R has good psycho-

metric properties and can discriminate between persons

diagnosed with an AN-like illness and bulimia nervosa.

Morgan-Russell [Hayward] Outcome Assessment

Schedule (MROAS29,30) is a structured interview con-

cerned with clinical factors central to the syndrome of

AN. We used a modified version,42 because additional

items provide a measure of binge/purge behaviors. The

MROAS is the most widely used outcome assessment

instrument in AN, and its graded outcome categories are

often used as a proxy measure of severity in AN.7

Marlowe-Crowne Social Desirability Scale (MCS43) is a

33-item instrument assessing the tendency to portray

oneself in a favorable light. It has good divergent validity

with measures of anxious and depressive psychopathol-

ogy,9 suggesting that it may be an appropriate candidate

against which to test the divergent validity of a measure

of psychopathology in AN.

Patient Health Questionnaire (PHQ45) is a self-report

instrument that can reliably diagnose mental disorders

among primary care patients.44 Because of the already

significant time burden placed on participants in this

study, the PHQ was chosen to assess co-morbid diagno-

ses. An adolescent version, the PHQ-A, has been vali-

dated for use with individuals between 13 and 18 years of

age,45 and this was used for participants below the age

of 18.

Obsessive Compulsive Inventory-Revised (OCI-R46) is

an 18-item self-administered questionnaire based on the

earlier 84-item OCI47 assessing both obsessions and

MAGUIRE ET AL.


compulsions commonly present in Obsessive Compul-

sive Disorder (OCD). The instrument has good conver-

gent validity and discriminates OCD from other anxiety

disorders.48,49 Foa et al.46 demonstrated good internal

consistency and test–retest reliability for the OCI-R in

clinical groups. A specific measure of this comorbid con-

dition was included given high rates of OCD in AN.50–52

Studies 1–4

Study 1. (Longitudinal; n 5 103). Participants in this

cohort were young (M 5 25.34 years; SD 5 8.63), with a

mean BMI at baseline of 16.08 (SD 5 2.32). Mean illness

duration was 8.69 years (SD 5 7.95; range 5 0–38), with

46.6% meeting full-criteria for AN, and 53.4% EDNOS-

AN. Just over half (51.5%) were classified as restricting

AN, with the remainder classified as binge/purging type.

After being administered the CASIAN, weight, height,

and medical status were confirmed using medical files or

the primary attending physician. Participants completed

a form assessing their treatment history and the follow-

ing measures: MROAS, EAT, MAC-R, PHQ, and OCI-R.

Their primary clinician was asked to rate their level of

engagement with treatment. These measures were used

to assess the convergent and concurrent validity of the

CASIAN. These longitudinal participants were then reas-

sessed 3 and 6 months later as part of the analysis of the

CASIAN’s predictive validity.

Study 2. (Cross-sectional; n 5 68). Participants in this

cohort were slightly younger (M 5 22.9 years, SD 5 6.9),

with a mean BMI at baseline of 17.0 (SD 5 2.5). Mean ill-

ness duration was 6.9 years (SD 5 6.8. Just over a third

(38.2%) met full-criteria for AN, with the remainder

meeting EDNOS-AN criteria. Exactly half of the sample

was classified as having restricting AN. As with Study 1,

after being administered the CASIAN, weight, height, and

medical status were confirmed using medical files, or the

Primary Care Physician. The cohort then completed the

MCS, a rating of socioeconomic status and a Subject Rat-

ing of Illness Severity. The participants Primary Clinician

were asked to complete a Clinician Rating of Illness Se-

verity. Data from this cohort were used to assess discrim-

inant and concurrent validity.

Study 3. Thirty consecutive consenting participants

from Study 1 also had their Time 1 CASIAN interviews

recorded on a digital voice recorder. The average age of

participants in this cohort was 24.1 years (SD 5 6.29),

with a mean BMI of 17.06 (SD 5 2.02) with an average

duration of illness of 8.4 years (SD 5 6.39; range 1–27).

These taped interviews were reviewed and independently

rated on the CASIAN by two health professionals; an

acknowledged expert and a novice. Rater 1 was a PhD

level clinical psychologist with over 20 years experience

in the treatment of eating disorders, and rater 2 was a

first year doctoral student in clinical psychology with no

experience in the assessment or treatment of eating dis-

orders. These data were used to assess interrater reliabil-

ity.

Study 4. Twenty-four consecutive consenting partici-

pants in Study 2 were readministered the CASIAN 1 week

after initial assessment. The average age of this cohort

was 22.79 years (SD 5 6.29), average BMI 17.39 (SD 5

2.3), and average duration of illness 6.69 years (SD 5

5.84; range, 1–27). A short time period was selected to

assess the stability because it was expected that con-

structs integral to the instrument (e.g., weight and food

intake) could be expected to vary over the course of

treatment. These data were used to assess test–retest

reliability.

Results

Item Analysis and Selection

Item Analysis Procedures. The item analyses wereconducted on the entire pooled sample (n 5 171).To determine the utility of each of the 34 items, anumber of formal and staged data analyses stepswere completed. First, frequencies and descriptivestatistics were generated for all items to identifyand remove those items with high rates of missingdata or no variance. No items were removed as aresult of this process. Next, correlations betweenCASIAN items and total scores on three other eat-ing disorder psychopathology questionnaires(MROAS [Average and General Outcome Score],EAT, and MAC-R) were examined to reveal anyitems failing to show relationships with thesemeasures. Next, corrected item-to-total correla-tions were analyzed to remove items that were notcorrelated or were negatively correlated with thetotal CASIAN score. An exploratory factor analysiswas then performed, forcing all items into a singlefactor, to determine which items failed to load evenat a moderate level (�.30) on this single factor.Finally, preliminary test–retest correlations wereconducted to determine any items showing partic-ularly poor test–retest performance.

Results of Item Analysis Procedures

Based on combined results of each of the aboveprocedures, two items were eliminated from fur-ther analysis. The first was ‘‘Time at LowestWeight’’: it showed poor associations with the othermeasures of eating disorder pathology, low item-to-total correlation, and it did not load even mod-erately on the single factor. Similarly, the item ‘‘Tol-erating Directives’’ performed poorly; minimal var-iance, weak associations with measures of other



eating disorder pathology, and, most importantly, avery low-test–retest correlation.

The objective bingeing item performed uni-formly poorly across analyses; low item-to-totalcorrelation, a low-single factor loading, and weakassociations with the other measures of eating dis-order pathology. The item assessing ‘‘SubjectiveBulimic Binge’’ also performed poorly across tests;item-to-total correlation was low, as was single fac-tor loading and correlations with other measures ofeating disorder pathology were weak. However, asboth of these items were deemed to be importantclinical variables, attempts were made to preservethem within the analysis. These two items werecombined and scores recoded assigning the maxi-mum subjective and/or objective frequency foreach case. This revised item called ‘‘MaximumBinge Frequency’’ underwent the same item analy-sis procedures described earlier and was includedin further analyses. All subsequent analyses wereconducted using the resultant 31-item CASIAN.

Factor Analysis

Exploratory Factor Analysis. As an initial investigationof the construct validity of the CASIAN, an explora-tory factor analysis was conducted. For this analy-sis, CASIAN item scores obtained for the total sam-ple (n 5 171) were used. The ‘‘Factor’’ procedure ofSPSS Version 1653 was used.

Extraction. Maximum likelihood analysis wasselected for factor extraction, because thisapproach provides a principal factor (as opposed toa principal component) solution and yields a statis-tical test of goodness-of-fit. Decisions about theretention of factors were guided by the Kaiser crite-rion,54 with eigenvalues [ 1 being retained. A six-factor solution accounting for 57.1% of the totalvariance was the best fit for the data. The good-ness-of-fit test for this solution reached statisticalsignificance (X2 5 411.098, df 5 294, p 5 .000) con-firming the utility of the six-factor structure.

Rotation. Promax was used as the method of rota-tion. Factors comprising ‘‘severity’’ in AN wereexpected to be correlated, and hence a nonorthog-onal rotation (rather than orthogonal), whichallows for correlated factors, was used.55 A moreconservative cut-off of .4 was used as the guidelinefor the minimum factor loading required for anitem.56 In addition, each variable was then requiredto load less than .4 on all other variables with aminimum difference between the highest loading(‘‘on factor’’) and next highest loading (‘‘off factor’’)for a variable of .2.

Following this initial factor analysis, ‘‘Interfer-ence Due to Preoccupations’’ was dropped as it didnot load significantly on any factor. An iterative se-ries of factor analyses were then conducted drop-ping one by one any item that did not meet theabove requirements. In total, eight further factoranalyses were run dropping sequentially the fol-lowing items: ‘‘Average Daily Intake,’’ ‘‘EgosyntonicAttachment,’’ ‘‘Intimacy,’’ ‘‘Protection of Habits,’’‘‘Medical Complications,’’ ‘‘Menstruation,’’ and‘‘Social Eating.’’ All these items failed to meet thefactor loading requirements outlined earlier. Thisresulted in a factor solution for a 23-item CASIAN,which also comprised six factors.

Interfactor Correlations. Interfactor correlationsranged from a very low, .035 to moderately high,.521 suggesting some evidence for a higher orderfactor representing severity but also separate com-ponents of illness that may work quite independ-ently. A lower cut-off of .32 and an upper cut-off of.8 for intercorrelations between factors are recom-mended57; with \.32 being a small and [.8 beinglarge. It is evident that the majority of intercorrela-tions were small, none were large, and two fell inthe moderate range. Overall, the results suggestedthat these are relatively independent factors.

Clinically Relevant Items Dropped

from the Analysis

A number of clinically relevant variables were notsupported psychometrically by the above analysis.The three items retained as clinically relevant, butwould not contribute to the overall severity score are‘‘Average Daily Intake’’ (3a), ‘‘Menstruation’’ (6a), andMedical Complications (6b). Nonetheless, these itemsmay be of theoretical importance to the concept ofseverity in AN. As this validation study uses a rela-tively small sample and is the first upon which factoranalyses for the CASIAN has been conducted, a con-servative approach to the elimination of items fromfurther analysis was adopted. Therefore, it wasdecided that these items should be part of the ques-tionnaire, but not part of the scoring for the instru-ment. This solution allows for the gathering of clinicaldata thought important to an investigation of severityand will therefore be available for future analyses,without sacrificing the psychometric properties of theinstrument. The abbreviated version of the 23 itemsto contribute to scoring and the three additional clini-cally relevant items retained (contact author for fullversion of the CASIAN) are given below.

Factor: Weight

� Current weight and height for BMI conversion(Current BMI)

MAGUIRE ET AL.


� What was your stable resting weight prior tothe commencement of weight losing behav-iors? (Premorbid Drop)

� What is the lowest weight you have reached sincethe onset ofweight loss? (Lowest BMI Ever)

� Over the past month what is the lowest weightyou have wanted to be? (Lowest Ideal BMI)

Factor: Motivation

� As you may know your minimum healthyweight is ____. How do you feel about the ideathat you should be at that weight? (Acceptanceof Normal Weight)

� How much weight are you prepared to gaineach week until you reach a healthy weight?How do you feel about 1 kg per week? (Accep-tance of Weight Gain)

� Say that you did feel motivated to get well andyou put your mind to it, do you feel like youcould reach a BMI of 20/normal resting weightor have you doubts about your ability to do it?(Self-Efficacy to Reach Normal Weight)

� Say that you did feel motivated to get well andyou put your mind to it, how much weight doyou think you could gain per week until youreached a normal weight? How confident doyou feel that you could gain a kilo a week?(Self-Efficacy to Gain Weight)

� Interviewer Rating: In your opinion is the per-son unmotivated to get well, somewhat moti-vated or very motivated to get or stay well?(Clinical Rating)

� How do you feel about your body when it is atits normal healthy resting weight? (Body Dis-satisfaction)

� Do you think that you are better off continuingwith your life just as it is at present? Wouldyou like to permanently change the eating dis-order? (Entrenchment)

Factor: Duration

� What age were you when you began to activelylose weight? At what age were you when yourweight losing behaviors began to lead toweight loss? (Illness Duration)

� Since onset has there been any period inwhich you have returned to your normalweight range and been eating disorder free?(Net Length of Illness)

Factor: Bulimic Behaviors

� Over the past month have you experiencedepisodes of eating where once you began to

eat you felt as if you could not stop or as if youhad lost control? (Maximum Binge Frequency)

� Over the past month have you ever madeyourself vomit or vomited spontaneously aftereating? (Self-Induced Vomiting)

Factor: Obsessionality

� How much of your day do you currentlyspend thinking about or ruminating on food,weight, shape, fat and body? (Obsessional EDThought)

� With regards the rules you follow around foodand exercise, if over the past month you havebroken one of those rules or circumstancesprevent you from sticking to them, how haveyou felt? (Regimentation of Diet)

� Over the past month, has your eating andexercise pattern been for the most part stable?(Stability of Weight Reduction Regime)

� Can you describe a typical week’s activity? Isthere any formal/structured exercise in theweek? What about incidental activity? (PhysicalActivity)

Factor: Acute Issues

� Have you lost weight in the last 6 months?How much? Over what time frame? (AcuteWeight Drop)

� How many times over the life of the illnesshave you lost 5 kg or more in less than 30days? (Precipitous Weight Loss)

� Over the past month have you used any laxa-tives, either natural forms such as licoriceand chewing gums or packet forms? (Laxa-tive Use)

� How would you describe your mood over thepast month? Have you felt sad, blue, downmore days than not? (Depression)

Clinically Relevant Items Not Contributing to Scoring

� Record a typical days intake (all food and liquid)over the pastmonth (AverageDaily Intake).

� Have you ever menstruated/had a period? Doyou get your periods at the moment? How reg-ularly? (Menstruation)

� List all the medical complications the personhas currently (Medical Complications)

Reliability of the CASIAN

The final 26-item CASIAN had high internal con-sistency (Cronbach’s a 5 .811), high test-retest reli-ability over a 1-week period (ICC 5 .957), and highinterrater reliability (ICC 5 .973).



Validity of the CASIAN

The extent to which the CASIAN measures ANseverity was assessed by investigating conver-gent, discriminant, concurrent, and predictivevalidity.

Convergent Validity.

The CASIAN total score correlated significantly withMROAS total score .319 (p 5 .000), along with thethree MROAS subscales, food intake .502 (p 5 .000),psychosexual 2.362 (p 5 .000), and socioeconomic2.318 (p\ .001 as well as the EAT Total Score .443 (p5 .000), and three subscales of the EAT, Dieting .347(p 5 .000), Bulimia .305 (p 5 .000), and Oral Control.326 (p 5 .000). The total score of the MAC-R wasalso significantly correlated with the CASIAN totalscore .273 (p\ .05). Additional support for the con-vergent validity of the CASIAN was evident in the sig-nificant correlations between the CASIAN total scoreand total number of inpatient admissions for an ED.186 (p \ .05), and total number of hospital days(general and ED) .251 (p5 .000).

Discriminant Validity. There was no significant cor-relation between the CASIAN and the Marlowe-Crowne Social Desirability Measure .049 (p 5 .25)or combined family income 2.309 (p5 .39).

Concurrent Validity. The total score of the CASIANwas positively and significantly correlated withboth the Primary Clinician Rating of Severity .431(p 5 .000) and the Subjects Rating of Illness Sever-ity .372 (p5 .001).

Predictive Validity. Table 1 shows that scoresobtained on the CASIAN at time 1 correlated signif-icantly with both scores on the CASIAN and othermeasures of eating disorder symtomatology (EAT,MAC-R, and MROAS) and weight change at both 3and 6-month follow-up

A series of hierarchical ordinary least squaresregression analyses explored the ability of theCASIAN to account for variance on these measuresadministered at follow-up times one (3 months)and two (6 months). Results of these analyses arereported in Table 2. Co-morbid psychopathologywas controlled for in these analyses; OCI-R TotalScore and PHQ/PHQ-A subscale scores assessingthe presence of a co-morbid depressive illness,panic, and/or anxiety disorder and alcohol abusewere entered into the first step of the regression,CASIAN Total Score at Time 1 was then entered atthe second step. A consistent pattern emerged:total CASIAN severity score at initial assessmentaccounted for a significant amount of the variancein scores at Time 2 and 3 on all other measure ofeating disorder symptomatology and psychopa-thology (MROAS, EAT, and MAC-R). Although theexamination of the ability of the total severity scoreat initial assessment to account for observedweight gain over the follow-up period was not sig-nificant for either time points, it approached signif-icance over the longer follow-up period.

Discussion

The aim of this study was to develop and explorethe psychometric properties of a multidimensionalmeasure specifically designed to assess severity inAN. This is a first necessary step to enable explora-tion of what components or axes may be importantin understanding illness severity. The study soughtto investigate the full dimension of illness byincluding individuals along the AN spectrum, notjust those meeting strict diagnostic criteria. The re-sultant CASIAN represents an attempt to describethe multiple features of AN that contribute to se-verity and to operationalize a method for assessingthe extent of those features. Rigorous and thorough

TABLE 1. Pearsons correlations between Time 1 CASIANTotal Score and follow-up CASIAN and eating disordersymptomatology measures

Measure CASIAN Total Score Time 1

CASIAN time 2 .668**

CASIAN time 3 .662**

MROAS average outcome time 2 2.456**

MROAS average outcome time 3 2.541**

EAT total time 2 .598**

EAT total time 3 .579**

MAC-R total time 2 .475**

MAC-R total time 3 .556**

Percent weight gain Time 1 to 2 .127Percent weight gain Time 1 to 3 .208*

* p\ .05,**p\ .01.

TABLE 2. Regression analyses (‘‘Enter’’) with CASIANTime 1 total score as predictor of eatingoutcome measures

MeasureR SquareChange

FChange

Significanceof F Change

CASIAN time 2 .174 43.607 .000CASIAN time 3 .310 40.186 .000MROAS average outcome time 2 .153 16.097 .000MROAS average outcome time 3 .205 20.070 .000EAT total time 2 .135 17.996 .000EAT total time 3 .134 16.359 .000MAC-R total time 2 .091 9.468 .003MAC-R total time 3 .146 16.647 .000Percent weight gain Time 1 to 2 .018 1.455 .231Percent weight gain Time 1 to 3 .050 3.744 .057

MAGUIRE ET AL.


instrument development processes and item analy-sis procedures were followed yielding a 23-iteminstrument, which was subjected to psychometricevaluation, with an additional three items of clini-cal importance included in the administration ofthe CASIAN but not contributing to scoring.

It would appear that the construct of severityinvolves multiple dimensions with factor analyticstudies here determining a six factor structure.Those factors comprising severity were motivation,weight, obsessionality, illness duration, bulimicbehaviors, and acute illness issues. Some low-to-moderate intercorrelations were observed betweenfactors that could be argued to be conceptuallyrelated (e.g., obsessionality and acute illness issues)but on the whole there appears to be evidence forboth independence of the factors and some higherorder factor accounting for variance across all sixfactors, which arguably could be severity.

The reliability of the CASIAN is supported by thehigh internal consistency of the CASIAN items,excellent 1-week stability, and very high interrateragreement. Given the nature of this instrument asclinician rated, and its likely use to assess illness se-verity and changes therein across different treat-ments and centers, high levels of interrater reliabil-ity are essential. The CASIAN is a distinct advance-ment in this regard to the MROAS, which, despitebeing interviewer rated, shows particularly poorinterrater reliability.58

Overall, the CASIAN observed a pattern of sig-nificant correlations with all the other instrumentsassessing eating disorder psychopathology. TheCASIAN as a whole demonstrated significant posi-tive relationships with both the clinician’s assess-ment of overall illness severity and the partici-pant’s own rating of the same, suggesting that theinstrument is providing an assessment of illnessseverity that matches clinical reality and indeedthe individual sufferers own subjective reality. TheCASIAN also demonstrated good discriminant va-lidity showing no significant relationships with ei-ther of the measures used in this study. The corre-lation between combined family income and theCASIAN while not significant was substantial, thisis likely the result of a recruitment bias, wherebythe most severe cases in this study were recruitedfrom public facilities and as such had a lower soci-oeconomic background. Finally, the CASIAN dem-onstrated an ability to predict the extent and in-tensity of eating disorder psychopathology at 3and 6-month follow-up, suggesting that theinstrument may hold promise as an indicator ofprognosis in this illness, although longer-term fol-low-up studies are needed.

The current study had a number of limitations.The first of these was the absence of a standardizeddiagnostic instrument in the test battery. Althoughmultiple endeavors were made to standardize diag-noses across sites and communication about eligi-bility for the study was maintained between allsites for the duration of the study, participants inthis study were diagnosed according to DSM-IV ANcriteria and adjusted EDNOS criteria by the pri-mary clinicians at their site and hence there mayhave been site differences in the application of thediagnostic system. Second, while the sample sizewas large for studies on AN, in terms of the samplesizes required for instrument development, thepresent sample was relatively small. Hence all find-ings need to be regarded as preliminary. Furthersamples are needed to conduct factor analyticstudies on a larger N to confirm the findings of thisstudy. The strengths of this study include the sam-ple method, which recruited from multiple treat-ment settings with differing clinical populations,providing for a large spread of illness severityacross the sample.

Although still requiring further evaluation, theCASIAN is the first multidimensional measure ofseverity in AN to be validated in the literature. Itoffers an alternative to the MROAS as an instru-ment to provide a measure of ED status. TheMROAS was devised over 20 years ago and hasbeen the subject of some criticism concerning itspsychometric properties.43,58 The current instru-ment is arguably an improvement over the MROASwith demonstrated reliability and validity. Further-more, the CASIAN takes account of the spectrum ofAN symptomatology including psychologicalaspects such as motivation, body image disturb-ance, and depression.

The findings of this study require replication andextension in other samples. Further factor analyticstudies are needed to confirm the factor structureof the CASIAN and contribute to further under-standing of and decisions about items retained onthe instrument. Importantly, studies of the long-term predictive utility of both the CASIAN as ameasure of severity and the staging model derivedfrom it are needed, before any conclusions can bedrawn about the ability of the either to provide areal indicator of illness severity in AN.

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Documents

The clinician administered staging instrument for anorexia nervosa: Development and psychometric properties