A COMPARISON BETWEEN COGNITIVE-BEHAVIORAL THERAPY AND EXPOSURE WITH RESPONSE PREVENTION IN THE TREATMENT OF BULIMIA NERVOSA

 

Katie Dudash

 

INTRODUCTION

            Bulimia nervosa is an eating disorder with psychological, physiological, developmental, and cultural components.  The disorder is commonly characterized by binge eating followed by inappropriate compensatory behaviors, such as self-induced vomiting, excessive exercise, fasting, and the misuse of diuretics, laxatives or enemas.  Patients properly diagnosed with bulimia nervosa endure many psychological and physiological problems.  In order to alleviate these problems for the patient, usually some type of intervention is required.  Considering the financial costs to the patient who seeks treatment, it is important to identify effective and efficient treatment programs.  Due to the wide variety of individual patient differences, it would be unwise to proclaim one treatment method as the universal cure for bulimia nervosa.  However, identifying what methods work under particular conditions may help therapists tailor an individualized treatment program after a careful assessment of the client.  Having this knowledge would potentially save both the client and the therapist a lot of time and frustration; not to mention, the patient would be on the path to recovery sooner.  Kaye et al (1999) stress the importance of making progress towards the understanding and treatment of anorexia and bulimia nervosa, in order to generate more specific and effective psychotherapies and pharmacologic interventions. 

            In this paper, I will present my analysis of two methods used to treat bulimia nervosa.  The first method is cognitive-behavioral therapy for bulimia nervosa; this method is quite popular among psychologists who specialize in the treatment of eating disorders.  The second method is called exposure with response prevention; this method is the product of behavior therapy and is used less frequently than cognitive-behavior therapy.  Both methods have been proven to be significantly effective in reducing the symptoms of bulimia nervosa.  Although immediate reduction of bulimic symptoms is beneficial to the patient, it is not indicative of recovery.  For this reason, my analysis will consider the long-term outcome effects for each treatment method.   My findings will influence which method I will recommend for the treatment of bulimia nervosa. 

 

COGNITIVE-BEHAVIORAL THERAPY: MOST POPULAR METHOD FOR THE TREATMENT OF BULIMIA NERVOSA

 

What is Cognitive-Behavioral Therapy

 

          In 1981, a researcher named Fairburn conducted the first study applying cognitive-behavioral therapy to the treatment of bulimia nervosa.  In a recently published report by D. L. Spangler (1999), CBT is touted as “a well-developed, theoretically grounded treatment for bulimia nervosa with the strongest empirical support for its efficacy of any form of treatment for bulimia nervosa.”  Today cognitive-behavioral therapy (CBT) is a form of therapy commonly used to treat patients with bulimia nervosa (BN). 

More specifically, CBT is normally structured as a series of interventions that addresses the cognitive aspects and the behavioral components of a particular disorder.  The cognitive-behavioral approach is based on a theoretical view, which “holds the patients’ beliefs about weight, shape and eating as central to the maintenance of bulimia nervosa…effective treatment, therefore, depends on altering patients’ assumptions about he importance of shape and weight” (Cooper & Steere, 1995).  Some of the other cognitive aspects that therapists should focus on are: preoccupation with the body and food, perfectionism, low self-esteem, etc. (McGilley & Pryor, 1998).   Therapists should also focus on the behavioral components of BN such as: disturbed eating habits, binge eating, purging, dieting, and ritualistic exercise.   In the case of BN, the initial goal of CBT is “to restore control over dietary intake” (McGilley & Pryor, 1998).  The logical explanation for this goal is that caloric restriction and dieting efforts tend to make patients more susceptible to binging if provoked by food cues.  By avoiding caloric restriction and dieting efforts, the urge to binge decreases for patients, especially when patients are eating a well-balanced, normal-sized diet.  Patients are typically directed to monitor and record the thoughts, feelings, and circumstances surrounding binge-purge episodes in a journal, which may then be analyzed by the therapist in order to provide the patient with constructive feedback.  Most forms of CBT recommend cessation of dieting efforts and adherence to a normal diet.  CBT also targets the patient’s tendency to link body weight with self-esteem. 

 

Is CBT effective in the treatment of Bulimia Nervosa?

 

McGilley and Pryor (1998) warn, “although cognitive-behavioral therapy is the first-line of treatment of choice for bulimia nervosa, its effectiveness is limited.”  McGilley and Pryor’s study (1998) reports that approximately 50 percent of patients who receive CBT stop binge eating and purging, while the remaining 50 percent show only partial improvement.  The latter 50 percent of patients who only show partial improvement may be suffering from a comorbid illness, which may effect the outcome of CBT.  More importantly, both researchers and patients need to keep in mind that BN is a difficult disorder to treatment.  In fact, the majority of patients experience post-treatment relapse(s) regardless of the type of treatment method used.  For this reason, both researchers and patients need to work together in order to construct more effective treatment approaches, guidelines, and interventions. 

The majority of research evidence on CBT supports the treatment program’s effectiveness in managing the symptoms of BN.  However, not all of the findings can or should be taken as fact.  Bulik et al (1998) conducted a study that evaluated the role of exposure with response prevention (ERP) in the cognitive-behavioral therapy treatment for BN.  Bulik et al (1998) reported CBT as “a highly effective treatment for BN;” whereas, exposure with response prevention “did not appear to offer any significant additive benefits that are proportional to the amount of effort required to implement the treatment.”  It is important to note that traditional CBT was administered before ERP treatment; hence, patients initially improved and then plateaued out when ERP was administered.  Perhaps, if ERP was administered as the primary treatment with traditional CBT to follow as the secondary treatment, the conclusions drawn in the Bulik et al (1998) study would have been exactly the opposite of what was actually reported.  That is, if ERP was administer first, then the patient’s improvement would have been attributed to ERP rather than CBT.  Just some food for thought (no pun intended). 

A study conducted by Steel et al (1995) reports that “while treatment has largely been effective at reducing binge purge frequencies, it does not result in the elimination of the presenting problem for a significant proportion of participants.”  So although the frequency of bulimic symptoms is reduced with implementation of CBT, this reduction does not constitute a recovery according to some therapists.  As a side note, the controversy seems to be over what constitutes or what defines a recovery for a patient diagnosed with bulimia nervosa.  Is it reduced symptomology of bulimia nervosa, complete elimination of symptoms with or without an occasional relapse? Is it the resumption of eating regular meals without dietary restrictions?  Is CBT too short?  How long should treatment continue? Should there be “maintenance” sessions?  Should CBT be combined with pharmological therapy and if so for how long?  These are the questions that perplex psychologists researching and treating eating disorders, such as bulimia nervosa.  The fact that these questions remain unanswered justifies why interventions are greatly needed.  Furthermore, since only 50 percent of the patients treated with CBT improve and fully recover, it becomes increasingly important to be able to accurately predict who will benefit from CBT and who will not benefit. 

 

What are the prognostic indicators for the outcome of CBT?

 

Leung et al (2000) reports “individuals who benefit less from CBT will be those who have more pathological core beliefs (unconditional beliefs, unrelated to food, shape, and weight).”  Leung et al (2000) suggest that CBT as applied in the treatment of BN may not work for some of the patients because the cognitive focus is too narrow.  Granted, bulimic symptoms are generally “precipitated and maintained by a set of maladaptive thinking patterns regarding body weight, size, and shape;” however, other factors such as maladaptive personalities, schemas, and other cognitive representations need to be considered when designing a patient’s treatment program (Leung et al, 2000). That is, patients with BN express a more general dysfunctional thinking style than just maladaptive beliefs regarding food, weight, and shape.  When placed in a group CBT condition, most bulimics show signs of improvement; however, those with more pathological core beliefs tend to have poorer outcomes after completing the prescribed treatment program (Leung et al, 2000).  The results of this study should be considered with caution.  The sample size (N = 20) is small, which tends to reduce the reliability of the results.  In addition, the patients received group CBT as opposed to individual CBT.  Perhaps the patients with “more pathological core beliefs” and who were identified as having poorer treatment outcomes would have done better had they received individual CBT and not group CBT. 

In the common pursuit of establishing appropriate treatment guidelines and increasing the efficacy of clinical intervention, Francisco J. Vaz report (1998) also provides some prognostic indicators of who will and will not do well in various treatment programs.  As do many of his colleagues, Vaz reports that while the majority of bulimics show a fair initial response to a wide variety of treatments, most tend to relapse despite the method of treatment used (1998).  More specifically, Vaz mentions several prognostic indicators linked to poorer outcome after treatment for the management of BN, including: intensity of vomiting, binge frequency, history of disorders, distorted body image, inability to maintain stable body weight, age of onset, duration of the illness, comorbidity with depression, substance abuse, low self-esteem, impulsiveness/ineffectiveness characteristics, etc (1998).  Vaz suggests that treatment should be intensified for individuals who show any of the aforementioned indicators (1998).  This intensification is especially important for patients with comorbid disorders, since comorbidity tends to complicate the treatment of BN.  Nevertheless, I would think that it is important to treat all patients who receive the diagnosis of BN with the same level of intensity.  All patients who are suffering from BN are presenting symptoms that indicate real problems, for this reason these patients should be given the best care available to ensure the best chances for recovery. 

 

EXPOSURE WITH RESPONSE PREVENTION: AN ALTERNATIVE TREATMENT FOR BULIMIA NERVOSA

 

What is Exposure with Response Prevention?

 

            Exposure with response prevention (ERP) is an alternative treatment approach designed to treat patients with bulimia nervosa or anorexia nervosa with the purging sub-type.  ERP involves “planned, sustained, and repetitive exposures” to forbidden foods followed by prevention measures, which prevent the patient from binging and/or purging (Kennedy et al, 1995).  There are two variations of ERP treatment.  One version is called exposure with response prevention of vomiting (ERP-V).  This treatment method involves exposing the patient to forbidden foods, and allowing the patient to eat as much of the food as desired.  The patient is then monitored and purging efforts are prevented.  Patient monitoring ceases when the patients’ urge to vomit subsides.  The other version of ERP is called exposure with response prevention of binging (ERP-B).  This particular treatment method involves exposing the patient to forbidden foods, and allowing the patient to touch, smell, lick, taste, but not binge on the food items.  The patient is monitored and binging is prevented until the urge to binge has subsided.  Studies conducted by Schmidt and Marks (1989) and Rosen and Leitenberg (1982) support the effectiveness of ERP-B.  ERP treatment programs strongly resemble the behavior methods used to desensitize people to personally distressing stimuli.  In fact, ERP may be classified best as a form of behavioral therapy. 

            Popularized in the 1960s, behavioral therapy focuses “only on aspects of human behavior that can be quantified; aspects of human behavior that are inferential (e.g., unconscious conflicts) cannot be reliably measured due to the lack of tangibility” (Sloan & Mizes, 1999).  The key principle of behavior therapy is that behavior is a function of its consequences.  If a behavior is reinforced, then the behavior is more likely to be repeated.  If a behavior is punished, then the patient is less likely to repeat the behavior. 

Applying this principle to treatment methods for eating disorders, one would conclude that if a person binges and then is able to reduce the feelings of anxiety about binging, and the fears of gaining weight by purging, then the purging behaviors will be reinforced.  Moreover, Rosen and Leitenberg suggest, “binging in bulimia nervosa is more a consequence of vomiting than vomiting is a consequence of binging” (1982).  That is, once a person has learned how to reduce anxiety about gaining weight via purging, the person will be more likely to binge because they can purge.  The goal of ERP, especially ERP-V, is to un-teach the self-destructive behaviors associated with BN.  Many behavior therapists believe that maladaptive behavior is more effectively changed “by doing, not talking, …by practicing new behaviors, as well as exposure to critical cues;” furthermore, “merely talking and gaining insight about behaviors does not necessarily result in change” (Sloan & Mizes, 1999).  Although behavior therapists strongly advocate action over cognitive exploration, many researchers agree that the cognitive aspects of human behavior are considered important in understanding psychopathology and its treatment (Sloan & Mizes, 1999). 

           

 

How effective is ERP is treating Bulimia Nervosa?

 

            As reported in Bulik et al (1998), a one year post treatment follow-up on patients treated with ERP-B indicated that treatment programs were most effective when the treatment goals include abstinence from binging and restricting, and decreasing the urge to binge in response to high risk cues.  In addition, Kennedy et al (1995), patients treated with ERP-B showed reductions in the urge to binge/vomit, anxiety levels, tension, guilt, depression, and lack of control.  These reductions provide support for the efficacy of ERP treatment methods for BN.  However, Kennedy et al (1995) also reported no change in the patients’ feelings of fatness either during the sessions or after treatment.  This last observation indicates that perhaps behavior therapy alone is not sufficient in curing BN. Considering that the risk of relapse might increase if feelings of fatness persist beyond treatment, a more cognitive or psychotherapeutic approach might be implemented for a more favorable outcome. 

            Although the data on ERP does indicate that the treatment provides some benefits to the patient, ERP is not the preferred method of treatment for BN.  ERP is both expensive and logistically complicated (Bulik et al, 1998).  The treatment setting is unrealistic and reactivity effects compromise the true results of the treatment (Kennedy et al, 1995).  Recall that in ERP treatment conditions, researchers monitor the subjects during and after exposure.  Bulik et al (1998) conclude that ERP therapy for BN fails to offer “any significant additive benefits proportional to the amount of effort required to implement the treatment.” 

            Furthermore, a study conducted by Cooper and Steere (1995) suggests that ERP therapy does contain cognitive elements, since every exposure session also included cognitive restructuring.  Likewise, Cooper and Steere point out that most cognitive behavioral therapies contain some elements of ERP therapy (1995).  Since these therapies tend to coexist, Cooper & Steere’s study (1995) isolated the two therapies to learn more about each treatment program’s effectiveness.  The results suggest that pure CBT was more effective than pre ERP therapy (Cooper & Steere, 1995).  In fact, Cooper and Steere report “virtually all the patients in the ERP group deteriorated after treatment and virtually none of the patients in the CBT group did” (1995). 

 

What are the predictors of outcome for ERP treatment?

 

            The predictors of poor outcome after a patient receives ERP treatment for BN include: history of obesity, presence of major depression, high scores on the Eating Disorders Inventory, pre-treatment global functioning, post-treatment binging, food restriction, etc. (Bulik et al, 1998).  The best predictor for favorable outcome for patients receiving ERP treatment for BN was a high level of self-directedness (Bulik et al, 1998).  These predictors, especially the level of self-directedness, suggest that a more cognitive approach to treating BN may yield more favorable results than a strictly behavioral treatment approach. 

 

CONCLUSIONS

 

            Given the information presented in this paper, I would recommend using cognitive-behavioral therapy rather than exposure with response prevention therapy for the treatment of bulimia nervosa.  Granted, more research is needed to improve guidelines used for the assessment and treatment of eating disorders.  This new information will help psychologists and psychotherapists design new treatment programs to maximize the outcome of clinical intervention.  I believe this paper has demonstrated that psychotherapists should not try to simplify a disorder for the purpose of a quick and easy treatment program.  People are complicated beings; people suffering from eating disorders are even more complicated.  Consequently, the care of patients diagnosed with eating disorders should draw upon “a comprehensive array of approaches” and treatment programs rather than limiting the potential benefits of therapy through adherence to a solitary treatment approach (Practice guideline for, 2000).   

 

REFERENCES

 

Bulik, C. M., Sullivan, P. F., Carter, F. A., McIntosh, V. V., & Joyce, P. R. (1998). 

Predictors of 1-year treatment outcome in bulimia nervosa.  Comprehensive Psychiatry, 39, 206-214.

 

Bulik, C. M., Sullivan, P. F., Carter, F. A., McIntosh, V. V., & Joyce, P. R. (1998). The

role of exposure with response prevention in the cognitive-behavioral therapy for bulimia nervosa.  Psychological Medicine, 28, 611-623. 

 

Cooper, P. J., & Steere, J. (1995). A comparison of two psychological treatments for

bulimia nervosa: Implications for models of maintenance.  Behavioral Research and Therapy, 33, 875-885. 

 

Kaye, W., Strober, M., Stein, D., & Gendall, K. (1999). New directions in treatment

            Research of anorexia and bulimia nervosa.  Biological Psychiatry, 45, 1285-1292.

 

Kennedy, S. H., Katz, R., Neitzert, C. S., Ralevski, E., & Mendlowitz, S. (1995).

Exposure with response prevention treatment of anorexia nervosa-bulimic subtype and bulimia nervosa.  Behavioral Research and Therapy, 33, 685-689. 

 

Leung, N., Waller, G., & Thomas, G. (2000). Outcome of group cognitive-behavior

therapy for bulimia nervosa: The role of core beliefs.  Behavior Research and Therapy, 38, 145-156.

 

McGilley, B. M., & Pryor, T. L. (1998).  Assessment and treatment of bulimia nervosa. 

            American Family Physician, 57, 2743-2750. 

 

Practice guideline for the treatment of patients with eating disorders (2000). The

 American Journal of Psychiatry, 157, 1-39. 

 

Rosen, J. C., & Leitenberg, H. (1982).  Bulimia nervosa: Treatment with exposure and

response prevention.  Behavior Therapy, 13, 117-124. 

 

Schmidt, U., & Marks, I. M. (1989).  Exposure plus prevention of bingeing vs. exposure

plus prevention of vomiting in bulimia nervosa: A crossover study.  Journal of Nervous and Mental Disease, 177, 259-266. 

 

Sloan, D. M., & Mizes, J. S. (1999). Foundations of behavior therapy in the

contemporary healthcare context.  Clinical Psychology Review, 19, 255-274.

 

Spangler, D. L. (1999).  Cognitive-behavioral therapy for bulimia nervosa: An illustration

            Journal of Clinical Psychology, 55, 699-713. 

 

Steel, Z. P., Farag, P. A., & Blaszczynski, A. P. (1995). Interrupting the binge-purge

cycle in bulimia: The use of planned binges.  International Journal of Eating Disorders, 18, 199-208. 

 

Vaz, F. J. (1998). Outcome of bulimia nervosa: Prognostic indicators.  Journal of

Psychosomatic Research, 45, 391-400.

 

Walsh, B. T., & Devlin, M. J. (1998).  Eating disorders: Progress and problems.  Science,

280, 1387-1390.  

 

 

 

 

 

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