Evidence of cognitive-behavioral therapy in the treatment of obese patients with binge eating disorder

Abstracts

OBJETIVOS: Avaliar as evidências sobre a eficácia da terapia cognitivo-comportamental no tratamento de obesos com transtorno da compulsão alimentar periódica. MÉTODOS: Nesta revisão, foram incluídos ensaios clínicos e metanálises publicados entre janeiro de 1980 e fevereiro de 2006, em todas as línguas. Foram excluídos estudos que investigassem a eficácia da terapia cognitivo-comportamental com uso concomitante de medicação, terapia cognitivo-comportamental no formato de manuais de auto-ajuda, relatos ou série de casos e cartas ao editor. As bases eletrônicas de dados consultadas foram: MEDLINE, PsycINFO, Embase, LILACS e Cochrane Library. A estratégia de busca incluiu também a checagem manual das referências bibliográficas dos artigos selecionados e de capítulos de livros sobre o tema. RESULTADOS: Foram encontrados dois ensaios clínicos abertos e 15 controlados. O desfecho primário na maioria desses estudos é a compulsão alimentar. No geral, os ensaios clínicos avaliados sugerem que o uso da terapia cognitivo-comportamental resulta numa melhora significativa da compulsão alimentar e dos sintomas psicopatológicos associados ao transtorno da compulsão alimentar periódica, sem resultar em perda de peso substancial. CONCLUSÕES: As evidências disponíveis sugerem que a terapia cognitivo-comportamental é um método de tratamento eficaz para o transtorno da compulsão alimentar, em relação aos componentes psicológicos dessa condição. Entretanto, sua eficácia na redução do peso corporal e na manutenção dos seus efeitos no longo prazo ainda precisa ser melhor investigada.

Terapia cognitivo-comportamental; tratamento, psicoterapia; transtorno da compulsão alimentar periódica; compulsão alimentar; obesidade

REVIEW ARTICLE

Evidence of cognitive–behavioral therapy in the treatment of obese patients with binge eating disorder

Mônica Duchesne^I; José Carlos Appolinário^I; Bernard Pimentel Rangé^II; Silvia Freitas^I; Marcelo Papelbaum^I; Walmir Coutinho^III

^IInstituto de Psiquiatria, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil. Group of Obesity and Eating Disorders, Instituto Estadual de Diabetes e Endocrinologia do Rio de Janeiro, Rio de Janeiro, RJ, Brazil

^IIInstituto de Psicologia, UFRJ, Rio de Janeiro, RJ, Brazil

^IIIGroup of Obesity and Eating Disorders, Instituto Estadual de Diabetes e Endocrinologia, Rio de Janeiro, RJ, Brazil

^{Correspondence}

ABSTRACT

OBJECTIVES: To investigate evidence of the efficacy of cognitive–behavioral therapy in the treatment of obese patients with binge eating disorder.

METHOD: This review included clinical trials and meta–analyses published in all languages from January 1980 to February 2006. Studies assessing the efficacy of cognitive–behavioral therapy associated with medication, cognitive–behavioral therapy in self–help manuals, case reports or series and letters to editors were excluded. The following electronic databases were used: MEDLINE, PsycINFO, Embase, LILACS and Cochrane Library. Search strategies also included consulting the references of selected articles and chapters of specialized books.

RESULTS: Two open and 15 controlled clinical trials were included. The primary outcome in most studies was binge eating. In general, the clinical trials suggest that cognitive–behavioral therapy results in significant improvement in binge eating and other psychopathological symptoms related to binge eating disorder. However, no substantial weight loss was reported.

CONCLUSIONS: Available evidence suggests that cognitive–behavioral therapy is an effective intervention method for psychological aspects of binge eating disorder, although its efficacy in body weight reduction and long–term maintenance of results still needs further investigation.

Keywords: Cognitive–behavioral therapy, treatment, psychotherapy, binge eating disorder, binge eating, obesity.

Introduction

Binge eating disorder (BED) is characterized by recurrent episodes of binge eating in the absence of inadequate compensatory behaviors to avoid weight gain observed in bulimia nervosa (BN). During a binge eating episode, there is a feeling of lack of control over the behavior associated with the ingestion of large amounts of food even if individuals are not hungry, leading to a great discomfort. This episode is followed by an intense subjective distress, characterized by feelings of anxiety, sadness, guilt and shame.¹

Despite weight is not a diagnostic criterion, BED is often associated with overweight and with various levels of obesity. Whereas its estimated prevalence in the general population can range from 1.8² to 4.6%,³ approximately 30% of obese individuals who seek treatment to lose weight have this disorder.^2,3 A positive association has been observed between presence of binge eating and increased adiposity.^3,4

Obese patients with BED, when compared with patients without BED, present more general or eating psychopathological symptoms.⁴ With regard to the former group, higher levels of perfectionism,⁵ impulsiveness,⁶ anxiety⁶ and social isolation⁶ have been identified, as well as more vulnerability to depression.^5,7–9 In addition, worst quality of life¹⁰ and poor self–esteem⁷ have been reported in this group of individuals. As to psychopathological symptoms specific of BED, more dysfunctional attitudes have been observed concerning nutrition and weight, besides extreme concern about and dissatisfaction with body shape.^4,5,8,11,12 Furthermore, evidence suggests that the subgroup of obese patients with BED presents worse response to therapies aimed at losing weight,^5,8,10,13,14 larger number of unsuccessful attempts of adherence to diets,^3,10 more difficulty in losing weight,^5,8,10,13,14 worse maintenance of lost weight^8,10,13,14 and higher rate of treatment dropout.⁸

Cognitive–behavioral therapy (CBT) was considered the most investigated form of psychotherapeutic intervention in BED using randomized clinical trials,¹⁵ and has been increasingly used in several specialized centers for the treatment of eating disorders. It is based on the assumption that a dysfunctional system of beliefs is associated with the development and maintenance of BED. Consequently, changes in distorted patterns of thinking and restructuring of overvalued beliefs associated with weight and body image are primary focuses of the therapy, and for that reason many cognitive techniques are used.

Besides cognitive techniques, CBT also uses behavioral techniques to help modify eating habits. Examples of these techniques are self–monitoring (systematic observation and register of ingested foods and associated circumstances), techniques to control stimuli (which involve identification of the situations that favor the occurrence of binge eating and development of a lifestyle that minimizes the patient's contact with such situations) and training in problem solving, which helps patients develop alternative strategies to face their difficulties without making use of inappropriate eating. In general, CBT also focuses on strategies to prevent recurrences.^16–19 Finally, although there are some differences in the way it has been used in different clinical trials, programs used in those studies are semi–structured, usually implemented in a group format (with approximately 10 patients) and mean duration of 12 90–minute sessions.

The present article aims at performing a critical review of the available literature on CBT applied to obese patients with BED, besides discussing changes in currently used treatment protocols.

Method

A literature review was performed using the following electronic databases: MEDLINE, PsycINFO, Embase, LILACS and Cochrane Library. The following medical subject heading (MeSH) term categories were used: binge, binge eating, binge eating disorder, bulimia nervosa, obesity and body image vs. cognitive–behavior therapy, cognitive therapy, behavior therapy, psychological support and relapse. Search strategies also included consulting the references of selected articles, searching for articles and book chapters of interest on this issue, with the ultimate goal of locating pertinent texts that had not been found by means of the electronic search. Open and controlled clinical trials and meta–analyses were included, published between January 1980 and February 2006 in all languages and assessing efficacy of CBT in BED therapy. Exclusion criteria were studies investigating efficacy of CBT in association with drugs, CBT as self–help manuals, letters to the editor and case reports or series.

The Diagnostic and Statistical Manual of Mental Disorders (DSM–IV)¹ specifies a binge eating frequency of at least 2 days a week, over a minimum period of 6 months to establish diagnosis of BED. However, DSM–IV criteria were only established in 1994, and consequently duration, frequency and severity of behavioral aspects associated with binge eating in obese patients investigated in clinical trials were varied in the first studies. Therefore, this review included articles using patients with BED, subclinical BED and obese with non–purgative BN. Those latter diagnostic categories are considered BED correlates.

Results

A total of 348 publications involving issues associated with CBT in BED were found. After an evaluation of abstracts, 84 articles were initially selected and requested in full text. After reading those articles, 18 studies in English were included in this review, because they met the inclusion criteria: two open studies, 15 controlled studies and one meta–analysis. Next, we describe the results of clinical trials using this form of psychotherapy in BED, focusing on the efficacy of CBT in associated and characteristic psychopathological symptoms of BED and on body weight.

Psychopathological symptoms characteristic of BED

Binge eating

The first evaluations of CBT efficacy adapted for obese patients with binge eating were performed in patients with non–purgative BN that presented episodes of binge eating twice a week, for at least 6 months, most of them with overweight or obesity.^20,21 For example, in a randomized controlled study including 44 patients (body mass index – BMI = 32.6), Telch et al.²⁰ observed 94% of reduction in frequency of binge eating after 10 CBT sessions, compared with 9% of reduction in patients allocated in a waiting list.

In obese patients with BED, open studies suggest that CBT in a group format favors reduction in frequency of binge eating, ranging between 80²² and 91%.²³ In addition, randomized controlled studies also reported significant reductions in binge eating frequency at the end of CBT.^11,12,24–27 Agras et al.²⁴ carried out a comparative study between CBT and interpersonal therapy (IT), a therapy format that focuses on increased ability to deal with interpersonal difficulties and with the social roles.²¹ Fifty patients were initially randomized for CBT or for a waiting list, with a 55% remission rate after 12 sessions of CBT (and 9% for the waiting list). The patients who still presented binge eating at the end of the therapy were given 12 additional sessions of IT, and the remaining were given 12 sessions of behavioral therapy (BT) focused on weight loss. The association between IT and BT did not result in additional improvement in binge eating. In another clinical trial, Eldredge et al.¹² observed a 50% reduction in frequency after 12 therapy sessions and 19.8% in a waiting list. One of the arms of this study involved offering patients who did not improve 12 additional sessions of CBT. At the end of 24 sessions, there was 68% reduction in binge eating and increase in remission rate (2/3 of patients).

Some randomized controlled studies compared the efficacy of CBT alone and CBT associated with drugs.^7,27–29 Those studies demonstrated significant reductions in binge eating after CBT, with no additional benefit with the association of desipramine,⁷ fluoxetine^27–29 or fluvoxamine.²⁷ Grilo et al.²⁹ randomized 108 patients to four conditions: CBT associated with fluoxetine, CBT associated with placebo, fluoxetine or placebo. They observed remission rates significantly higher in CBT groups, with no significant improvement in the group receiving fluoxetine or placebo with no CBT. Remission rates were: 29% (fluoxetine), 30% (placebo), 55% (CBT associated with fluoxetine) and 73% (CBT associated with placebo). In another study, also using CBT, Devlin et al.²⁸ compared the efficacy of adding fluoxetine or CBT to a BT program. A significant improvement in binge eating was observed as a result of adding CBT, with 62% of patients receiving CBT reaching remission (and 33% in the control group). No significant difference in remission rates was observed adding fluoxetine compared with placebo.

Kenardy et al.³⁰ studied the efficacy of CBT in obese patients with type 2 diabetes who presented binge eating for at least once a week. Comparing CBT to a treatment based on the principles of self–knowledge and self–acceptance by Rogers,³¹ they demonstrated that both treatments were efficacious in reducing binge eating frequency, with remission rate of 47% at the end of CBT and 29% in the alternative treatment. Furthermore, they observed that improvement in binge eating was associated with improvement in glycemic control.

Besides reduction in frequency of binge eating episodes, reduction in binge eating severity was assessed in many studies using the Binge Eating Scale.³² Randomized controlled studies identified a reduction in binge eating severity as a result of CBT, compared with BT³³ and waiting lists.^12,24 Therefore, previously described clinical trials suggest that CBT results in significant reduction in frequency and severity of binge eating.

Attitudes associated with eating and body shape

Besides binge eating, some clinical trials investigated other dysfunctional behaviors and attitudes associated with eating, body weight and shape in obese patients with BED.^{11,12,22–27,29,30,33–35} One of the assessed aspects is the attempt (generally unsuccessful) of inappropriately restricting eating to lose weight. Using the subscale Cognitive Restraint of the Three–Factor Eating Questionnaire,³⁶ Smith et al.²³ did not observe improvement in tendency to restrict eating in nine patients who received 16 CBT sessions. Using the same subscale, Eldredge et al.,¹² Agras et al.²⁴ and Grilo et al.²⁹ did not observe changes in levels of food restriction either, when comparing group CBT results with a waiting list or with a group receiving fluoxetine. However, some randomized controlled studies showed improvement in restriction and adoption of more flexible attitudes towards nutrition.^11,26,27,33 For example, Ricca et al.²⁷ randomly allocated 107 patients into five treatment conditions: CBT alone, CBT associated with fluoxetine, CBT associated with fluvoxamine, fluoxetine without CBT and fluvoxamine without CBT. Using the subscale Restraint of the Eating Disorder Examination,³⁷ they observed significant reduction in food restriction levels and dysfunctional concern about nutrition in patients submitted to CBT alone and to CBT associated with psychotropics, but there was no improvement in patients receiving fluoxetine or fluvoxamine alone.

Studies comparing CBT and CBT associated with nutritional guidance^34,35 revealed significant reduction in tendency to present binge eating, assessed using the subscale Bulimia of the Eating Disorder Inventory.³⁸ Moreover, in controlled studies comparing CBT and waiting list,^12,24 CBT and BT⁷, and CBT and fluoxetine,²⁹ patients reported increased control of impulse to eat inappropriately, assessed using the subscale Disinhibition of the Three–Factor Eating Questionnaire.³⁶ Stunkard et al.³⁶ described that improvement in scores of that subscale was associated with effective increase in ability to control nutrition when individuals are exposed to emotionally stressing situations (which could favor occurrence of binge eating). Those data are particularly interesting, since, according to Fairburn et al.,¹⁶ Lowe & Caputo³⁹ and Laessle et al.,⁴⁰ reduction in restriction levels and improvement in ability to control impulses to eat excessively present a positive correlation with higher success in controlling binge eating and nutrition in general.

Open^22,23 and controlled^{11,27,29,30,34,35} studies comparing CBT to IT, a therapy based on Rogers' principles or psychotropics, reported significant reduction in extreme concern about body weight and shape, and increased satisfaction about body image at the end of CBT.^{11,27,29,30,34,35} CBT was superior when compared with fluoxetine^27,29 and fluvoxamine²⁷ and had similar effects to those obtained by the other two types of therapy investigated. In some clinical trials, increase in satisfaction level about body shape occurred even in the absence of weight loss.^8,22,30 Studies on CBT in obese patients without BED^41,42 also revealed that improvement in satisfaction about body image was not correlated with BMI. Those findings led Wolff & Clark²² and Parham⁴³ to suggest that dissatisfaction levels about body image could be more correlated with the individual's belief system than with obesity level, stressing the importance of including strategies to change belief system on therapy programs, with the aim of improving patients' relationship with their body image.

Analysis of described clinical trials suggests that use of CBT results in significant reduction in dysfunctional concern about nutrition, weight and body shape, besides favoring improvement in attitudes associated with nutrition.

General psychopathological symptoms associated with BED

Some clinical trials assessed the results obtained by CBT in interpersonal functioning, self–esteem, depression and anxiety levels of patients with BED.^{10–12,21,23,25,27,30,33–35}

In a study comparing CBT and a waiting list, Eldredge et al.¹² did not report improvement in depression levels after 24 therapy sessions. However, an open study²³ and several randomized controlled studies^{25,27,29,33–35} using obese patients with BED described significant improvement in depression levels at the end of CBT. For example, Ricca et al.²⁷ used the Beck Depression Inventory⁴⁴ and reported that, although CBT had not been primarily focused on mood improvement, there was significant and equivalent reduction in depression levels in groups receiving CBT and CBT associated with fluoxetine or fluvoxamine. These authors suggested that reduction in binge eating and in dissatisfaction with body image resulting from CBT may have contributed to mood improvement in obese patients with BED.

Two clinical trials showed that CBT favors reduction in anxiety levels.^27,35 However, Fossati et al.³⁴ did not report significant improvement in anxiety levels after CBT in patients who received CBT alone or associated with nutrition. On the other hand, there was a significant decrease in anxiety levels in a group treated with CBT associated with nutritional guidance and exercises.

Some randomized and controlled studies indicated improvement in interpersonal difficulties,^{11,12,34,35,45} self–esteem¹¹ and social functioning as a result of group CBT. Using the Rosenberg Self–Esteem Questionnaire⁴⁶ and the Inventory of Interpersonal Problems,⁴⁷ Eldredge et al.¹² compared CBT with a waiting list and reported significant improvement in interpersonal relationships. However, in this study, there was no report of improvement in self–esteem.

Kenardy et al.,³⁰ assessing 34 diabetic obese patients with binge eating, observed improvement in the feeling of subjective well–being measured by the Well–Being Questionnaire,⁴⁸ which was adapted to diabetic patients. In another study, Marchesini et al.⁴⁵ reported improvement in quality of life perception in obese patients with BED, measured by the SF–36.⁴⁹ By comparing a CBT program followed by BT with a waiting list, they observed that all SF–36 subscales significantly improved in the CBT group and remained stable in the control group. In an open study, Wolff & Clark²² reported significant improvement in self–efficacy of 20 patients with BED after a 15–week CBT program.

The group of data presented above suggests that, at the end of CBT, there is improvement in interpersonal difficulties, level of social adaptation, self–esteem, anxiety and depression levels, besides improvement in quality of life and feeling of subjective well–being.

Body weight

Fourteen clinical trials investigated the results obtained by CBT over body weight in patients with BED. In two open studies^22,23 and 10 controlled studies,^{11,12,20,21,24–26,28,29,34} there was no significant reduction in body weight. For example, Agras et al.²⁴ compared a 12–week CBT program with a waiting list and, at the end of the therapy, did not report reduction in patients' BMI. Conversely, two controlled studies reported significant reductions in weight.^19,27,30 For example, Ricca et al.²⁷ observed a 5–point reduction in BMI of obese patients with BED who underwent CBT or CBT associated with fluoxetine or fluvoxamine, with no significant differences between groups.

Efficacy in associating nutritional guidance and physical activity with CBT was assessed in three randomized controlled studies, with significant reductions in body weight being observed using that association.^25,34,35 Fossati et al.³⁴ observed mean loss of 1.5 kg in a group of CBT associated with nutritional guidance; 2.8 kg in a group that underwent CBT, nutritional guidance and physical activity; and did not observe weight loss in the group undergoing CBT alone (0.3 kg).

Another line of research demonstrated that the association of BT programs subsequently to CBT favors weight loss. BT programs do not include techniques focused on modification of overvalued ideas associated with body weight and shape, but use the behavioral techniques previously mentioned in describing CBT programs. They emphasize strategies that favor weight loss, encourage food restriction and, in some studies, are associated with hypocaloric diets. Agras et al.²⁴ submitted patients in binge eating remission after 12 CBT sessions to a 12–session BT program, observing mean loss of 4.1 kg at the end of BT.

When analyzing patients' individual response profile to CBT, improvement in binge eating is significantly correlated with weight loss.^25,33,45 In general, the patients who presented remission or significant reduction in frequency of binge eating lose weight, whereas those who do not obtain reduction usually gain weight.^{11,14,23,24,26,28,29} Agras et al.²⁶ reported that total remission of binge eating was correlated with weight loss with 92% probability, whereas other reduction levels were associated with 60% or less chance of weight loss.

CBT results on binge eating and on body weight are presented in Table 1.

Long–term maintenance of CBT results

Some follow–up studies assessed maintenance of CBT results in periods ranging from 10 weeks to 1 year.^{11,20,21,25–27,30,33,52}

Clinical trials comparing CBT with a waiting list or with IT indicate that, during follow–up, there is an increase in frequency of binge eating.^11,20,21 However, the frequency remains in levels lower than those observed at the start of CBT.^11,20,21 Wilfley et al.¹¹ reported that obese patients with BED treated with CBT and IT presented increased binge eating after the end of the therapy, and remission rates were 72% in CBT and 70% in IT at the end of the 1–year follow–up (and 82% in CBT and 74% in IT at the end of the therapy). On the other hand, there was maintenance of improvements obtained in other psychopathological symptoms characteristic of BED, and an additional improvement in interpersonal difficulties. In this study, during follow–up there was statistically significant weight loss, although not clinically significant, in both therapies.

Three randomized and controlled studies reported maintenance of improvements obtained after the therapy.^25,27,30 In a clinical trial including 114 obese women with BED, Pendleton et al.²⁵ reported that remission rate remained stable during a 6–month follow–up (61% in the group of patients who underwent CBT associated with physical exercise vs. 30% in CBT alone). Those authors also observed that additional maintenance sessions every 2 weeks for 6 months after the end of CBT favored maintenance of weight loss. In general, at the end of follow–up, patients who underwent CBT associated with physical exercise, followed by maintenance, presented the highest reduction in BMI of all groups (– 2.26). In addition, all groups presented maintenance of improvement in depression levels, which was significantly correlated with improvement in binge eating. In another clinical trial, Kenardy et al.³⁰ compared CBT with a therapy based on Rogers' principles and followed patients with subclinical BED and type 2 diabetes for 3 months. Although both therapies had resulted in maintenance of improvements obtained in mood and BMI, the remission rate increased in CBT (47.1% at the end of therapy and 58.8% at the end of follow–up) and, conversely, there was significant worsening of binge eating in the therapy based on Rogers' principles (29.4% after the therapy and 17.6% in the follow–up).

Investigating the results obtained by the association of CBT with BT, Agras et al.⁵³ assessed 93 obese women with BED, 52 weeks after the end of therapy, and concluded that there was good maintenance of reduction in binge eating frequency (72% at the end of therapy and 64% at the end of follow–up) and in remission rates (41% at the end of therapy and 33% at the end of follow–up). However, there was increase in weight, which returned to baseline levels.

The positive relationship between binge eating frequency and weight loss, observed at the end of therapy, also occurred in the follow–up.^11,25,52 For example, in the study by Agras et al.,⁵³ patients who maintained remission during follow–up lost 6.4 kg; those with partial maintenance lost 4.1 kg; whereas those who had recurrence of binge eating gained 0.4 kg in the follow–up.

Analysis of results of the studies mentioned in this section suggests that, at the end of up to 1–year follow–ups, binge eating remains in lower levels than those observed at the start of therapy. It was also observed maintenance of improvement obtained in restriction levels;^11,27,34,52 ability to inhibit impulse of eating inappropriately;⁵² dysfunctional attitudes associated with nutrition, weight and body shape;^11,27 depression levels^27,52 and interpersonal difficulties.^11,52 However, there is a tendency for weight regain, which is directly associated with the fact that patients maintain episodes of binge eating in the follow–up.

Discussion

Analysis of results of clinical trials previously described suggests that after CBT there is improvement in general psychological functioning in patients with BED. Significant reductions were described in psychopathological symptoms characteristic of eating disorders and in associated symptoms. However, there was no significant reduction in body weight.

The results described in the present article are aligned with those observed in a meta–analysis carried out by Hay et al.⁵⁴ That meta–analysis studied the importance of different psychotherapy models to treat BN and syndromes with recurrent binge eating. The authors analyzed 28 clinical trials including patients with bulimia, four including patients with eating disorder with no other specification (one with BED) and three including patients with BED. After CBT, there was improvement in binge eating and depressive symptoms, with no changes in body weight. The authors concluded that there is evidence about the efficacy of CBT in the treatment of BN and BED. However, they stressed that the number of randomized and controlled clinical trials assessing the efficacy of CBT in BED is too small and, for that, it is necessary to perform more studies to create a more solid body of evidence.

Although all open and controlled studies had demonstrated that there is reduction in frequency of binge eating in treated groups, some patients do not improve with CBT or improve only partially. Furthermore, in the long term, there were different response profiles, and some patients presented worsening of binge eating after the end of therapy and, conversely, others showed improvement or remission at the end of up to 1–year follow–up periods.^30,53 In the study by Agras et al.,⁵³ of the 31 obese patients with BED who had remitted after the therapy, 45% remained in remission after a 1–year follow–up, 29% presented binge eating not more than once a week, and 26% had recurrences. On the other hand, 25% of the patients who still presented binge eating after the end of CBT had remission in the follow–up period. These data suggest that, for some patients, the techniques tested in clinical trials and therapy duration (usually 12 sessions) are sufficient. Nevertheless, for those who have no response, the use of other therapy models or changes in CBT programs currently used in studies could be considered.

Several changes in therapy programs have been suggested, with the aim of improving results obtained with CBT. Some authors suggested that a larger number of sessions could increase therapy efficacy.^12,25 Eldredge et al.¹² and Pendleton et al.²⁵ demonstrated that adding 12 sessions increased the number of patients who improved with CBT in the short term and in the 6–month follow–up period. Longer therapy programs allow an increase in the focus given to cognitive techniques that favor cognitive restructuring. This could reduce recurrence of binge eating, since restructuring of dysfunctional beliefs associated with nutrition, weight and body shape is related to better maintenance of long–term results.^14,52 For example, BT that does not include cognitive restructuring can help reducing short–term binge eating; however, its efficacy is limited in other psychopathological symptoms characteristic of BED, and its results tend not to be maintained in the long term.^{5,8,14,26,45,52,55}

Psychotherapeutic approaches focusing on interpersonal issues or emphasizing training in affection regulation favor reductions in binge eating frequency in obese patients with BED.^56,57 In general clinical practice, CBT uses a wide variety of techniques to approach interpersonal difficulties and strategies to provide patients with the possibility of regulating affections. However, those aspects did not receive much focus on therapy formats tested in clinical trials including patients with BED. Further studies could assess the efficacy of including techniques focused on those issues in existing therapy programs. Moreover, the fact that some patients do not improve with additional techniques focused on interpersonal aspects should be considered,²⁴ besides the fact that others do not improve after therapy programs focused on teaching mood regulation.⁵⁷ On the other hand, 12 CBT sessions are enough for some patients and not for others. Those data suggest that patients with BED have different response profiles. There has been no evidence of factors that could reliably predict therapy success, so that patient's profile could be adapted to the best therapy format.⁵⁸ Wilson⁵⁸ suggested that the therapy could be offered in modules, according to the difficulties of each patient. Initially, minimal interventions would be used (psychoeducation, self–help manuals or brief treatment protocols); subsequently, modules focusing on specific difficulties for patients who presented worse response to briefer interventions would be added.

Little impact obtained by CBT in patients' BMI could be a consequence of therapy formats used in most clinical trials. Based on the idea that BED and BN share characteristics, initial therapy proposal was adapting to BED the therapeutic model that proved to be efficacious in the treatment of BN. Consequently, strategies focused on weight loss were not extensively included. Primary treatment goals were reduction in binge eating frequency and improvement in other psychopathological symptoms characteristic of BED. Some CBT programs advise patients to focus on weight loss after having controlled binge eating.^16,20 Initial assumption was that the premature focus in terms of weight loss could encourage an increase in food restriction and that this would be a predisposing factor for the occurrence of binge eating.

As the profile of patients with BED has been studied, it was observed that, although food restriction can favor the occurrence of binge eating in some patients, such effect is not observed in all cases.^5,41 This fact can be exemplified by the results obtained in studies associating BT with diets encouraging food restriction. Besides being successful in reducing body weight,^{5,14,24,26,47} BT can promote some short–term improvement in binge eating.^14,24 In addition, studies associating CBT with structured programs of nutritional guidance and physical activity observed weight loss and improvement in binge eating.^25,34,35 Those data suggest that the inclusion of strategies focused on weight loss is not necessarily opposed to the treatment of psychopathological symptoms characteristic of BED and that CBT may increase its goals in order to also include weight loss. Devlin⁵⁹ proposed a therapy using two associated lines of activity. On the one hand, behavioral and cognitive strategies are implemented, focusing on normalization of nutrition, elimination of binge eating and weight loss. On the other hand, patients are helped to examine and reassess their attitudes towards appearance, their beliefs on personal value and their overvalued ideas about obesity. The treatment aims at reducing the distance between sustainable weight range and the weight considered acceptable by the patient. The importance of achieving a balance between changes and self–acceptance of individual limitations is implicit in this program.

Another important aspect concerning studies using CBT in BED is that most clinical trials used programs of group therapy. More studies assessing efficacy of CBT when individually implemented are necessary, since it facilitates treatment flexibility, adapting it to patient's profile. Another aspect that is little studied in clinical trials is the inclusion of the family in treatment programs or the establishment of other networks of social support.

Some CBT formats assessed in clinical trials did not include strategies focused on maintenance of results, and in those that included them, the number of sessions dedicated to this issue ranged between one and six. However, more emphasis on the development of techniques to prevent recurrences could increase the number of patients able to maintain results in the long term. More studies are necessary to identify the ideal amount of support after the end of the treatment, being occasionally useful to maintain spaced sessions to reinforce the therapy for long periods of time.

There are few clinical trials assessing efficacy of CBT in BED,⁵⁴ and some methodological limitations should be considered. In most clinical trials, samples are small.⁵⁴ In addition, the results of CBT were predominantly assessed in American and European women, aged between 18 and 65 years and BMI equal or higher than 27, making generalization of results to other populations difficult. Moreover, alcohol or drug dependence is a common exclusion factor, and more studies are necessary to assess CBT results in patients with those comorbid conditions. Finally, studies using follow–ups longer than 1 year will allow better assessment of CBT long–term effects.

Conclusions

CBT programs result in significant improvements in psychopathological symptoms characteristic of BED, with no significant reductions in body weight. There are also improvements in self–esteem, interpersonal difficulties, mood and quality of life, besides increased feeling of subjective well–being. However, not all patients have good response to CBT, and some adaptations in treatment protocols were suggested, with the aim of increasing the number of respondents. Such changes include insertion of techniques focused on weight loss and to give more emphasis to training techniques for mood regulation and to interpersonal issues. The ideal number of sessions has not been clearly defined yet, as well as the sequence in which techniques should be implemented, how many sessions should be dedicated to behavioral strategies and how many should be dedicated to cognitive strategies. In addition, it is still necessary to identify predictive factors of therapy success, so that it is possible to adapt specific protocols to individual response profiles. Achieving losses of weight that are maintained in the long term is part of the larger challenge of developing efficacious methods of weight maintenance for obese patients in general.

There are fewer studies on the efficacy of CBT in the treatment of BED when compared with BN studies. However, among the models proposed for BED, CBT is the model with more well documented results. In general, CBT is an efficacious treatment method for BED, and any other therapeutic model with which it has been compared proved to be significantly more efficacious.

References

Received July 10, 2006.

Accepted January 30, 2007.

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Publication Dates

• Publication in this collection
  06 Sept 2007
• Date of issue
  Apr 2007

History

• Accepted
  30 Jan 2007
• Received
  10 July 2006