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A Randomized Comparison of Group Cognitive-Behavioral Therapy and Group Interpersonal Psychotherapy for the Treatment of Overweight Individuals With Binge-Eating Disorder
Denise E. Wilfley, PhD;
R. Robinson Welch, PhD;
Richard I. Stein, PhD;
Emily Borman Spurrell, PhD;
Lisa R. Cohen, PhD;
Brian E. Saelens, PhD;
Jennifer Zoler Dounchis, BA;
Mary Ann Frank, PhD;
Claire V. Wiseman, PhD;
Georg E. Matt, PhD
Arch Gen Psychiatry. 2002;59:713-721.
ABSTRACT
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Background Cognitive-behavioral therapy (CBT) has documented efficacy for the treatment
of binge eating disorder (BED). Interpersonal psychotherapy (IPT) has been
shown to reduce binge eating but its long-term impact and time course on other
BED-related symptoms remain largely unknown. This study compares the effects
of group CBT and group IPT across BED-related symptoms among overweight individuals
with BED.
Methods One hundred sixty-two overweight patients meeting DSM-IV criteria for BED were randomly assigned to 20 weekly sessions
of either group CBT or group IPT. Assessments of binge eating and associated
eating disorder psychopathology, general psychological functioning, and weight
occurred before treatment, at posttreatment, and at 4-month intervals up to
12 months following treatment.
Results Binge-eating recovery rates were equivalent for CBT and IPT at posttreatment
(64 [79%] of 81 vs 59 [73%] of 81) and at 1-year follow-up (48 [59%] of 81
vs 50 [62%] of 81). Binge eating increased slightly through follow-up but
remained significantly below pretreatment levels. Across treatments, patients
had similar significant reductions in associated eating disorders and psychiatric
symptoms and maintenance of gains through follow-up. Dietary restraint decreased
more quickly in CBT but IPT had equivalent levels by later follow-ups. Patients'
relative weight decreased significantly but only slightly, with the greatest
reduction among patients sustaining recovery from binge eating from posttreatment
to 1-year follow-up.
Conclusions Group IPT is a viable alternative to group CBT for the treatment of
overweight patients with BED. Although lacking a nonspecific control condition
limits conclusions about treatment specificity, both treatments showed initial
and long-term efficacy for the core and related symptoms of BED.
INTRODUCTION
BINGE-EATING disorder (BED) is characterized by frequent and persistent
overeating episodes that are accompanied by feelings of loss of control and
marked distress, in the absence of regular compensatory behaviors.1 The prevalence of BED in the general population is
1.5% to 2.0%.2-3 Individuals with
BED typically present to treatment with the multiple problems of binge eating,
eating disorder psychopathology (eg, extreme concerns about eating, shape,
and weight), psychiatric symptoms, and overweight.4-5
Accordingly, treatments for BED need to impact these multiple domains in both
the short- and long-term.
Cognitive behavioral therapy (CBT) is the most well-established psychotherapeutic
treatment for BED.6-8
Interpersonal psychotherapy (IPT) has been examined as an alternative treatment
to target BED by directly addressing the social and interpersonal deficits
observed among these individuals.9-10
Both CBT and IPT for BED provide greater short-term efficacy than wait-list
control groups for the reduction of binge eating.10-13
The only comparison between active psychological treatments for BED that included
follow-up to 12 months after treatment cessation has been between CBT and
IPT.10 No immediate or long-term differences
between IPT and CBT for binge-eating outcomes were found.
The present study evaluates whether the prior study's findings comparing
CBT and IPT in the treatment of BED10 were
reliable, especially given its modest sample size. Using a substantially larger
sample than previously examined, we also sought to expand on prior BED research
by simultaneously (1) using the most valid assessment of BED and specific
eating disorder psychopathology, (2) evaluating time course repeatedly across
multidimensional symptomatology through the 1-year follow-up, and (3) assessing
the proposed mode specificity of these procedurally distinct treatments in
reducing binge eating (ie, CBT through reducing problematic eating-, shape-,
and weight-related attitudes and behaviors; IPT through improvements in interpersonal
functioning, negative mood, and self-esteem).10, 14
SUBJECTS AND METHODS
SUBJECTS
This study was conducted at eating disorder clinics at Yale University
(New Haven, Conn) and at San Diego State University (San Diego, Calif) and
approved by the institutional review board at each university. Recruitment
was conducted through media publicizing "compulsive overeating" treatment.
Individuals telephoning the clinics were preliminarily screened for inclusion
criteria (Table 1). Consent was
obtained at the initial clinic visit; DSM-IV BED
diagnosis and other study eligibility criteria were confirmed via interviews.
Nine hundred seventy-four individuals expressed initial interest; 320 remained
eligible based on telephone screens, and 195 met criteria after being interviewed.
Of these, 162 were interested, eligible, and randomized (Figure 1). Participants were randomly assigned within each of the
9 cohorts of 18 people to form 2 groups (IPT and CBT) of 9 participants each.
Specifically, the 18 slots for a given cohort were blocked by sex and then
randomly designated either IPT or CBT. Next, eligible participants were assigned
to a given slot based on the order in which they were accepted into the study.
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Table 1. Inclusion Criteria
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Figure 1. Summary of participant flow. BED
indicates binge-eating disorder; CBT, cognitive-behavioral therapy; and IPT,
interpersonal psychotherapy.
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TREATMENTS
Both treatments consisted of twenty 90-minute, weekly group sessions
and 3 individual sessions specifically addressing each participant's goals
and progress. These standardized supplemental meetings occurred at critical
time points (ie, pretreatment, midtreatment, and posttreatment) and were consistent
with the stage and focus of each treatment. Patients also received weekly
personalized, written feedback detailing progress. Groups were led by 2 therapists,
at least one of whom was at the doctoral level (the second being either at
the doctoral level or a psychology doctoral student). Therapists followed
treatment manuals and were trained by Bruce Rounsaville, MD (IPT) and G. Terence
Wilson, MD (CBT) (D.E.W. et al, unpublished data, 1996; D.E.W., unpublished
data, 1993; and reference 15). One of us (D.E.W.) provided session-by-session
supervision and feedback on each session's audiotapes to ensure manual adherence.
All IPT groups and 6 of the 9 CBT groups were led by a therapist who conducted
each treatment at some point.
Group CBT
Group CBT for BED is a triphasic, focal psychotherapy. In the first
phase (sessions 1-6), behavioral strategies (eg, self-monitoring) help patients
identify episodes of overrestriction and underrestriction and encourage normalization
of eating patterns. During the second phase (sessions 7-14), patients learn
cognitive skills to counter negative thoughts identified as predisposing binge
eating. Cognitive restructuring helps patients challenge harsh stereotyped
views of overweight and promotes acceptance of diverse body sizes. In the
third phase (sessions 15-20), relapse prevention techniques, such as problem
solving and coping with high-risk situations, are presented to help with maintaining
changes. Patients are encouraged to identify reasonable goals and strategies
for weight loss that will not promote binge eating.
Group IPT
Interpersonal psychotherapy is a brief, focused treatment16
adapted for BED and group format.10, 15, 17
Interpersonal psychotherapy focuses on problem resolution within 4 social
domains: grief, interpersonal role disputes, role transitions, and interpersonal
deficits. The initial phase (sessions 1-5) involves examination of a patient's
interpersonal history to identify the interpersonal problem area(s) associated
with BED onset and maintenance, and a detailed plan is provided for the patient
to work on specified problem area(s). Interpersonal deficits was the primary
problem area for many IPT patients (49 [60.5%] of 81), followed by interpersonal
role disputes (24 [29.6%] of 81), grief (5 [6.2%] of 81), and role transitions
(3 [3.7%] of 81). During the intermediate phase of treatment (sessions 6-15),
strategies are implemented to help patients make changes in identified problem
areas. In the termination phase (sessions 16-20), patients evaluate and consolidate
gains, detail plans for maintaining improvements, and outline remaining work.
ASSESSMENTS AND PROCEDURES
Measures were administered at all time points, except assessment of
non–eating disorder diagnostic psychiatric comorbidity, which occurred
only at pretreatment. Posttreatment assessment occurred immediately following
treatment cessation (median, 0.5 months), and follow-up assessments were approximately
4 (median, 4.7), 8 (median, 8.7), and 12 (median, 12.6) months after treatment
cessation. Structured clinical interviews were conducted by experienced assessors
trained specifically in the interviews. The assessors (bachelor level or higher)
had no therapeutic relationship with any of the participants they assessed.
Although we attempted to keep assessors unaware of group assignment, this
was not possible in all cases. To minimize this potential problem, assessors
received ongoing supervision to ensure standardized administration of the
interviews and underwent extensive training from the developers of the Eating
Disorder Examination (EDE) (Christopher Fairburn, MD) and the Structured Clinical
Interview for the DSM-III-R (Michael First, MD, Columbia
University, New York, NY). Dr Fairburn also provided annual calibration workshops
and ongoing EDE consultation. Interviews were audiotaped and randomly selected
to evaluate coding accuracy at weekly supervisions by 2 of us (D.E.W. and
R.R.W).
Eating Disorder Psychopathology
The EDE, 12th edition (12.0D),18 is an
interview that assesses eating disorder psychopathology. It was adapted in
accordance with DSM-IV research criteria to diagnose
BED and was used to track changes in binge eating and eating disorder psychopathology.
Binge-eating days were considered to be the number of days during the previous
28 on which at least 1 objective bulimic episode (OBE) occurred, as defined
by the consumption of an unusually large amount of food given the circumstances,
accompanied by loss of control over eating.18
Eating disorder psychopathology was assessed by the EDE subscales of dietary
restraint, eating concern, shape concern, and weight concern. Interrater reliability,
assessed via 36 (18 pretreatment, 18 follow-up) randomly selected EDE interviews,
revealed average interrater reliability (intraclass correlations) for subscales
and number of binge-eating days from 0.83 to 0.99 (all P<.001). The Cohen  for pretreatment diagnosis of BED was
1.00 (P<.001).
General Psychopathology
The Structured Clinical Interview for the DSM-III-R19-20 is a semistructured
interview designed to assess current and lifetime psychiatric disorders. The
Symptom Checklist-90–Revised21 assesses
psychiatric symptoms, the mean of which was standardized based on outpatient
sex-specific clinical norms.
Body Mass Index
Weight was assessed on a Detecto (Cardinal Scale Manufacturing Co, Webb
City, Mo) balance-beam scale; height was measured with a stadiometer. Body
mass index (BMI) was calculated as weight in kilograms divided by the square
of height in meters.
Self-esteem and Social Functioning
The Rosenberg Self-Esteem Questionnaire22
provided a measure of self-esteem. The Inventory of Interpersonal Problems23 measured level of interpersonal problems. The Social
Adjustment Scale24 assessed current social
functioning.
Suitability of Treatment
Before being informed of treatment assignment (already made at this
point), participants read brief treatment descriptions and indicated their
treatment preference. Using Likert-type scales from 1 to 10, participants
also rated the degree to which each treatment made sense and their confidence
in each treatment's success in reducing binge eating.
Integrity of Treatment
Following all treatment, 2 independent raters coded 9 CBT and 9 IPT
audiotaped sessions using 30 items adapted from an integrity scale used to
differentiate IPT and CBT for depression (S. D. Hollon, PhD, unpublished data,
1991). Neither rater was a therapist in this study, but both were trained
in the delivery of the 2 treatments. Therapists were blind to which session
was to be selected for rating treatment integrity, which was session 11 from
each cohort. Raters were 100% accurate in judging actual treatment modality
(ie, IPT vs CBT), and the treatment-specific indices significantly differentiated
the treatments, whereas the nonspecific index did not (Table 2).
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Table 2. Treatment Integrity Ratings*
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STATISTICAL ANALYSES
The completer sample size at posttreatment (n = 78 for CBT, n = 80 for
IPT) provided 80% power to detect a treatment difference of greater than or
equal to 0.8 binge days (d = 0.45), and at 12-month follow-up (n = 67 for
CBT, n = 71 for IPT), a difference of greater than or equal to 1.8 binge days
(d = 0.48).
Statistical analyses, using STATA version 6,25
were based on the generalized estimating equation (GEE) approach,26-27 an extension of generalized linear
models. With the GEE approach, participants with missing data at some, but
not all, time points remain in the analyses. The GEEs tested hypotheses about
treatment effects, time course, and treatment x time interactions, with
linear, quadratic, and cubic components of time as the within-subjects factors,
and treatment and interactions between time components and treatment as between-subjects
factors. Higher-order terms were only included in the analyses of the follow-up
period because the analyses of change from pretreatment to posttreatment were
based on only 2 assessment time points. All higher-order terms were tested
in the presence of lower-order terms. Interactions were analyzed using tests
with 1 degree of freedom per interaction, comparing the model with the interaction
term with a model that had all of the same terms except the interaction. An
exchangeable error variance-covariance matrix was assumed in all cases. A
2-tailed  level of .05 was used for all statistical tests. Data were
considered missing if not collected by 17.5 months following treatment cessation,
to avoid the effects of a possible assessment-availability bias on treatment
effects and time course. This was the case for 5 participants whose 12-month
data were excluded from all completer analyses.
The primary analyses included the posttreatment and follow-up time points
for 3 outcomes: recovered (ie, no OBEs in the last month), improved to subclinical
binge eating (ie, fewer than 4 OBE days in the last month),28-29
and being at or below a comparative level of eating disorder attitudes and
behaviors. The latter rating was made based on whether the global scale of
eating disorder psychopathology was at or below the mean of the 4 EDE subscales
reported for a non-BED, overweight, treatment-seeking sample of 115 participants
(20% male) with a mean BMI of 36.3 kg/m2 and age of 40.8 years.30 Given the dichotomous nature of the variables we
defined for the outcomes in these analyses (eg, recovered vs not recovered),
changes over time were analyzed using GEE logistic regression models (ie,
logit link function and binomial error distribution). Intent-to-treat (Figure 2, Figure 3, and Figure 4)
and completer analyses were used to test treatment differences at each time
point for each of these 3 categorical outcomes.
For each secondary outcome, 2 GEEs were conducted: 1 evaluating change
from pretreatment to posttreatment and 1 evaluating change from posttreatment
through 12-month follow-up. Analyses with binge eating (days/episodes) were
modeled based on an identity link function and the Poisson error distribution,
to accurately reflect the count nature of these outcomes, including the high
proportion of zero values at posttreatment and follow-up time points. Analyses
with other outcomes were modeled based on the identity link function and a
standard Gaussian error distribution. Completer analyses included data from
all available assessment time points for each participant, irrespective of
treatment completion. Data are given as mean ± SD unless otherwise
indicated.
RESULTS
RANDOMIZATION AND ATTRITION
Treatment groups did not significantly differ on demographics (Table 3) or on pretreatment level of any
outcome (all P values  .01) (Table 4). In addition, there were no significant site effects on
any outcome at baseline or across time.
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Table 3. Sample Characteristics at Baseline*
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Table 4. Treatment Outcomes by Time Point and Treatment*
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Therapy credibility ratings for CBT (8.8 ± 1.7) and IPT (8.6
± 1.9) indicated that both treatment rationales made sense to patients,
with no significant differences (t157=
0.95, P = .34) between the 2 treatments. In addition,
there were no significant differences (t157= 0.97, P = .34) in how confident patients
felt that CBT (7.0 ± 2.3) or IPT (6.8 ± 2.2) would be successful.
Ratings of treatment preference indicated that 46.5% of participants preferred
CBT, while 53.5% preferred IPT.
Sixteen patients (9.9%) dropped out of treatment: 9 (11.1%) from the
CBT group and 7 (8.6%) from the IPT group, a nonsignificant difference ( 21= 0.28, P = .6). There were no
significant treatment differences in compliance (t158= -1.91, P = .06), with CBT participants
attending 16.6 ± 3.7 sessions (83.0%) and IPT participants attending
17.7 ± 3.7 sessions (88.5%). Posttreatment interviews were conducted
with 158 (97.5%) of the 162 participants. For the 4 through 12-month follow-ups,
155 participants (95.7%) were available for at least 1 follow-up interview,
147 (90.7%) for at least 2 follow-ups, and 133 (82.1%) completed all 3 follow-ups.
The number of follow-up assessments completed (2.7 ± 0.8 of 3) did
not differ by treatment (t160= -0.93, P = .35).
TREATMENT OUTCOME
Primary Outcomes
Generalized estimating equation analyses revealed that there were no
significant treatment x time interactions for any of the 3 categorical
outcomes (all P values .15). The predicted probability
of being recovered decreased from approximately 78% to 65% from posttreatment
to about 9 months following treatment cessation, remaining stable through
12 months following treatment cessation. For recovery, there was a significant
quadratic time effect (P = .03) for the follow-up
period, reflecting a slight decline in the probability of being recovered
toward the end of the 12-month follow-up assessments. The probability of binge
eating at less than a clinically significant level decreased from approximately
91% to 84% from posttreatment to 12 months following treatment cessation.
For this outcome, there was a significant linear time effect (P = .007) for the follow-up period, reflecting a slight decrease in
the probability of bingeing at or below the subclinical level. The probability
of being at or below the normative level of global eating disorder psychopathology
remained stable from posttreatment across the follow-up period (all P values .73).
Intent-to-treat (Figure 2, Figure 3, and Figure 4) and completer rates for these 3 outcomes did not differ
by treatment at any time point (all P values .100);
intent-to-treat rates are reported in Figure
2, Figure 3, and Figure 4. Completer rates indicated that
64 (82%) of 78 CBT patients and 59 (74%) of 80 IPT patients were abstinent
from binge eating at posttreatment; 48 (72%) of 67 and 50 (70%) of 71, respectively,
were abstinent at the 12-month follow-up. In addition, at posttreatment, 73
(94%) of 78 CBT and 72 (90%) of 80 IPT patients were binge eating at less
than a clinically-significant level of 4 days per month; 56 (84%) of 67 and
63 (89%) of 71, respectively, were so improved at 12-month follow-up. Finally,
66 (85%) of 78 CBT and 60 (75%) of 80 IPT patients were found at posttreatment
to have global eating disorder psychopathology at or below a sample of patients
who were obese and not bingeing, thus substantially improved from baseline
rates of 23 (28%) of 81 for CBT and 22 (27%) of 81 for IPT. At 12-month follow-up,
these rates were 54 (82%) of 66 and 56 (79%) of 71, respectively.
Secondary Outcomes
For completers, binge eating decreased by 96% from pretreatment to posttreatment
for CBT and by 94% for IPT. At the 12-month follow-up, binge eating was reduced
by 90% and 93% for CBT and IPT patients, respectively, from pretreatment levels.
Cognitive-behavioral therapy and IPT were both effective in reducing number
of binge days during treatment ( = -.27; SE = 0.007; z = -11.68, P<.001), with no significant
treatment-by-time interaction (z = 0.11, P = .91). Significant quadratic ( = -.02; SE = 0.004; z = -4.82, P<.001) and
cubic ( = .002; SE = 0.007; z = 3.11, P = .002) time effects occurred through follow-up, with
no significant linear or higher-order treatment-by-time interactions (all P values .2). The pattern of results indicated an increase
during the first 6 months of follow-up from about 0.5 to 2.0 binge days per
month across treatments, a maintained level of binge eating 6 through 12 months
following treatment cessation, and a slight upward trajectory toward the end
of 12-month follow-up assessments (similar pattern detected for binge episodes).
Observed mean numbers of binge days are presented along with SDs (Table 4), but the medians of 16 at pretreatment
and zero at all posttreatment and follow-up time points are a better measure
of central tendency than the mean because of high skewedness.
All other secondary outcomes showed a significant improvement from pretreatment
to posttreatment (linear time effects, all P values
<.001) except for BMI, which remained stable during the course of treatment.
Results indicated that both CBT and IPT participants significantly reduced
their levels of dietary restraint during treatment but had a different time
course from posttreatment through the follow-up period. Specifically, CBT
was stable during the follow-up period, while IPT was significantly greater
than that of CBT at posttreatment and 4-month follow-up; however, the treatment
groups were indistinguishable on this outcome thereafter. All other outcomes
showed no treatment main or interaction effects from pretreatment to posttreatment
or posttreatment through follow-up. In addition, all of these outcomes remained
stable across follow-up, except interpersonal problems, which continued to
improve, and BMI, which decreased (Table
4). The number of patients who received additional treatment for
binge eating (CBT, n = 3; IPT, n = 8) was not significantly different (21= 2.52, P = .11). These patients
received individual psychotherapy, except one IPT patient, who received pharmacotherapy.
In post hoc analyses of binge eating, removing those patients who received
additional treatment did not change results.
Binge-eating abstinence was significantly related to BMI change, as
those participants who were abstinent at posttreatment had reduced their BMI
by 0.5 ± 1.5 kg/m2 during the course of treatment, while
those who were nonabstinent at posttreatment had increased their BMI by 0.4
± 2.0 kg/m2 (t151= -2.33, P = .02). Similarly, of the participants who were abstinent
at posttreatment, those who were abstinent at 12-month follow-up (n = 77)
had further decreased their BMI by 1.0 ± 3.0 kg/m2, whereas
those who were no longer abstinent at 12-month follow-up (n = 26) had increased
their BMI by 0.7 ± 2.9 kg/m2 (t104= -2.61, P = .01).
COMMENT
Interpersonal psychotherapy and CBT demonstrated equivalent, substantial
improvements in the short- and long-term across the core symptomatology and
associated problematic psychosocial functioning that characterizes BED. Treatment
efficacy for binge eating was best at posttreatment, with slight increases
in binge eating across both treatments during follow-up. At 12 months' posttreatment,
intent-to-treat rates of recovery from binge eating (98 [61%] of 162), and
the percentage of participants who had reduced binge eating to less than once
weekly (123 [76%] of 162), did not differ significantly by treatment modality.
Interpersonal psychotherapy took longer to achieve its full effects on dietary
restraint than did CBT; but by the last 2 follow-up assessments, IPT had reached
parity with CBT on this outcome. The equivalence of IPT and CBT on binge-eating
replicates an earlier IPT and CBT BED treatment comparison study.10
The lack of differences in binge-eating change or time course between
groups IPT and CBT for BED likely reflects a true similarity in their efficacy.
The relatively large BED treatment sample and high retention allowed power
to detect clinically meaningful treatment differences. In addition, outcome
concordance occurred despite marked differences in the focus and delivery
of CBT and IPT, as monitored throughout treatment and confirmed by blind independent
ratings of treatment integrity.
Results extend prior findings by documenting similarity between CBT
and IPT in the degree of and time course for decreases in most of the BED-related
eating- and weight/shape-related attitudinal disturbances. The exception to
treatment similarity—CBT's faster action on dietary restraint—is
consistent with CBT's direct focus on reducing behaviors and cognitions that
constitute excessive restriction of intake. This time course difference suggests
that these distinct treatment modalities may be operating differently, although
it is interesting to note that both treatments achieved high efficacy for
multiple problems, even those not directly targeted by the intervention. For
example, CBT resulted in changes in interpersonal functioning, as did IPT,
despite this area being addressed only in IPT. In the same way, IPT resulted
in sustained decreases in cognitive disturbances about eating, shape, and
weight even though the intervention did not directly address these attitudinal
problems. Moreover, both treatments incurred equivalent short- and long-term
improvements in general psychological functioning.
During follow-up, CBT and IPT resulted in statistically, but not clinically,31 significant decreases in BMI on average across the
entire sample. Nevertheless, weight maintenance is itself a positive outcome
since individuals with BED likely experience a trajectory of weight gain.32 Furthermore, approximately one fourth of treated
individuals lost more than 5% of their body weight, which has been associated
with health benefits.31 Our findings and those
of others33 also suggest that patients with
BED who cease binge eating tend to lose the most weight. For instance, among
individuals recovered from binge eating at posttreatment, those who remained
recovered at the 12-month follow-up had lost weight during the course of follow-up
(-5.3 lb [2.4 kg]), whereas those who were no longer recovered at the
end of follow-up had gained weight (+4.6 lb [2.1 kg]).
A comparative design testing active treatments (CBT, IPT) for BED was
selected for this study because both treatments have demonstrated superiority
to wait-listed control conditions, which are marked by persistent levels of
binge eating and BED-related symptoms.10-13,34-35
However, the comparative design prevents determining whether CBT and IPT had
specific effects for the treatment of BED. Unlike wait-listed conditions,
a nonspecific treatment condition would control not only for assessments and
the passage of time but also for patient expectation effects and other nonspecific
therapeutic influences. The issue of treatment specificity has become increasingly
relevant to BED treatment since some36-38
(but not all39) pharmacological studies of
BED have evidenced short-term placebo response. Also, a recent natural-course
study suggests relatively low long-term stability of BED among young, and
partly subthreshold, individuals with DSM-IV BED.32
Some recent specificity findings for the treatment of BED do exist.
Among obese patients with BED, cognitive therapy has been found to result
in higher binge-eating abstinence than behavioral therapy 6 months following
treatment.40 In addition, CBT was significantly
more effective than a credible nonspecific psychotherapy treatment in a pilot
study of recurrent binge eaters (most of whom met DSM-IV BED criteria) (J. Kenardy, PhD, et al, unpublished data, 2000). Nonetheless,
larger specificity studies are still needed as are those examining the specificity
of IPT. Also unknown are the characteristics of individuals with BED who may
be more or less responsive to nonspecific intervention or require a specific
treatment approach. Further, BED treatment research needs to examine generalizability
across different samples since most studies to date have enrolled samples
that are predominantly well educated and white.41
More information is clearly needed about the mechanisms by which CBT
and IPT treat the multiple problems inherent in BED. The remarkable similarity
in effectiveness and time course of CBT and IPT raises the possibility that
they operate through shared mechanisms in the treatment of BED but does not
necessarily indicate a similarity in treatment processes between them. In
this study, we examined the mode-specific effects of each treatment at posttreatment
and across follow-up; it may be that specificity occurred earlier, as recent
research on bulimia nervosa has demonstrated.42
Clearly, future studies are required to assess potential mediators throughout
the course of treatment.
The present reductions in binge eating and abstinence rates posttreatment
and through the follow-up period are among the highest reported in the treatment
research literature for BED.8 There were no
long-term treatment differences in binge eating, dietary restraint, or other
associated psychopathology. While both IPT and CBT facilitated slight average
decreases in relative weight, abstinence from binge eating resulted in the
most substantial weight loss. Binge-eating disorder was shown among earlier
studies to be highly responsive to CBT,10, 12-13
and our study indicates that IPT is an equivalent treatment alternative. Group
CBT and group IPT have positive effects across the multiple domains of problematic
functioning that characterize this disabling disorder.
AUTHOR INFORMATION
Submitted for publication November 20, 2000; final revision received
September 17, 2001; accepted October 12, 2001.
This research was supported by grants R29MH51384 and R29MH138403 from
the National Institute of Mental Health, Bethesda, Md.
This study was presented in part at the Eating Disorders Research Society
Annual Meeting, San Diego, Calif, November 20, 1999.
We thank Susan Beren, PhD, Michael Friedman, PhD, Anna Jost, BA, Danyte
Mockus, MPH, Marlene Schwartz, PhD, and Marian Tanofsky, MA, for their assistance
in the execution and analysis of this study. We are indebted to Christopher
G. Fairburn, MD, and G. Terence Wilson, PhD, for their invaluable training
of assessors and therapists, respectively. We give special thanks to Kelly
D. Brownell for his support of the project and to Bruce J. Rounsaville, MD,
for his significant contribution to the scientific quality of this project
and helpful comments on a previous draft of this manuscript. We are grateful
to Jamie Manwaring, BA, and Andrea Waldron, BA, for their help in the preparation
of this manuscript.
Corresponding author and reprints: Denise E. Wilfley, PhD, San Diego
State University/University of California–San Diego Joint Doctoral Clinical
Psychology Training Program, 6363 Alvarado Ct, Suite 103, San Diego, CA 92120
(e-mail: dwilfley{at}psychology.sdsu.edu).
From the Joint Doctoral Program in Clinical Psychology, San Diego State
University and University of California, San Diego (Drs Wilfley, Welch, Stein,
and Matt, and Ms Dounchis); Brown University, Providence, RI (Dr Spurrell);
Anxiety and Traumatic Stress Program, Payne Whitney Clinic, New York Presbyterian
Hospital, New York City (Dr Cohen); Division of Psychology, Children's Hospital
Medical Center, Cincinnati, Ohio (Dr Saelens); Department of Psychology, Yale
University, New Haven, Conn (Dr Frank); and the Department of Psychology,
Trinity College, Hartford, Conn (Dr Wiseman).
REFERENCES
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0.85;
all P values 
