Cognitive behaviour therapy for eating disorders: A transdiagnostic theory and treatment

In order to treat bulimia nervosa to a better extent, it is proposed that the disorders mechanisms need to be looked at more closely. Clinical perfectionism, core low self-esteem, mood intolerance, and interpersonal difficulties are the four mechanisms that need to be taken into account when considering the maintenance of bulimia nervosa. There are common mechanisms across all eating disorders but bulimia nervosa is the best studied, which makes it the point of focus.

The Cognitive behavioural therapy underlies the theory of cognitive behaviour which states that bulimia nervosa is due to a maladaptive judgment of one’s own self-worth. Most self-worth is drawn from patients shape and weight or control over eating habits. It is a dysfunctional system of evaluation. Binge eating is seen as coming from the ‘fasting phase’; their strict dietaries. One cookie more can be perceived as total loss of control and thus lead to a binge. However, binging is also supposed to have a neutralizing effect on patients, it can in dealing with life’s difficulties. To get rid of the calories taken in, patients engage in compensatory action (vomiting, sports, or laxatives). Another maintaining factor of the disorder is the high standards that these people set for themselves. The control over their body, shape, and weight must be flawless otherwise their self-esteem drops again. Evidence for the theory is:

• The effective treatment of cognitive behavioural therapy.

• Data that shows most relapse for those who evaluate themselves mainly on weight and shape.

• Less restrictions in diet led to fewer binges.

• Not targeting these core maintaining factors brought up less success in treatment.

• A cross-sectional structural equation modelling study about the maladaptive relationships.

• A study showing; the higher the base-line over-evaluation of weight, the higher the likelihood of ongoing bulimia nervosa.

The treatment based on the theory does not only focus on the binge eating but also on the general eating patterns (dietary) and on the over-evaluation of weight and shape as well as on dealing with difficult mood state. 15-20 sessions over five months are believed to be sufficient for treating bulimia nervosa. There has been a lot of research on the effectiveness of the treatment. 40-50% of the patients who completed the treatment (80%) stopped binging. It provides better outcomes than drugs or delayed treatment and is better or as effective as most other therapies (Interpersonal psychotherapy shows similar results). The best predictors of successful treatment are the frequency of binges (the more the harder) and that initial reduction of those. It is clear, that CBT is an effective treatment so far for bulimia nervosa, however there is still a large number of patients who do not respond to it.

It is unlikely that the theory is incorrect or the treatment falsely applied. The most reasonable explanation is that the disorder can in some cases be resistant to change. A possible way to make the treatment more effective is to make use of the new generic procedures for it. Furthermore, some procedures (body checking) need to be emphasized more during the treatment as those can be important for maintenance. Building upon the fact that initial success predicts good outcomes, the opening sessions could be more frequent (twice a week). Another proposal to why the theory does not work well enough at the moment, is that it needs to be extended. The four mechanisms mentioned at the start may need to be modified as part of an effective treatment.

Clinical perfectionism

The need to achieve highly demanding goals based on body shape and eating control in order to feel worth has already been established in the theory. It is further supposed that these goals are not limited to body matters but also to other important parts of their lives (work performance etc.). It is coupled with a fear of failure and frequent checking of their performance. As they are highly critical, their performance is never good enough which in turn leads to higher goals and stricter engagement in striving to meet them.

Core low self-esteem

As mentioned, most patients are highly self-critical and their self-evaluation mostly negative. The recurrent negative appraisal of their performance leads to a core low self-esteem which becomes chronic. It is this factor that makes changes very hard to achieve. They feel hopeless and tend to over-generalize failure which makes compliance to the treatment difficult.

Mood intolerance

Mood intolerance is a similar concept as ‘neutralizing mood states’ which was suggested in the cognitive theory, with the extension of all kinds of moods. Depression, anger, and anxiety but also intense excitement can lead to binging and or vomiting as it lessens the awareness of the original trigger and related thoughts. Other forms of neutralizing consist of taking substances or self-injury. These forms are also common among patients with eating disorders. Cognitions about the mood change also affect behaviour, e.g. ‘I cannot deal with this emotion’.

Interpersonal difficulties

The importance of this factor became salient with the success of IPT. Family tension for example is likely to trigger a need for control in children or an environment where slimness is demanded may magnify the concerns about weight. It has been proposed that bulimia nervosa patients are especially sensitive to social interactions and that adverse interactions also contribute to low self-esteem and compensatory actions (binging and purging). In some cases the eating disorders undermined the normal development of adolescence and IPT tries to reverse this via ‘role transition’. The feeling of being able to influence one’s own interpersonal life also helps overcome the disorder.

The transdiagnostic perspective

Anorexia nervosa

Patients suffering from anorexia nervosa have the same core psychopathology. They over-evaluate their weight and shape, restrict food, and vomit or misuse laxatives. Also binge eating is a feature of anorexia. The differences however lies in the steadiness of their under and over-eating and the effect on body weight. Anorexic patients have a very low body weight and can show symptoms of starvation. A cross-over to bulimia is very common for patients with anorexia. Some even call anorexia a ‘phase’. It is mostly present in early adolescence while bulimia starts later during late adolescence or early adulthood.

Atypical eating disorders or EDNOS

These eating disorders (not otherwise specified) are as common as anorexia or bulimia. They also show the same cognitive and behavioural patterns as in bulimia nervosa. One outcome of bulimia might be a cross-over to an atypical eating disorder where the criteria for bulimia are not fully met but symptoms of a disorder are still present.

Proposals for the transdiagnostic maintenance factors of eating disorders

It is supposed that common mechanisms underlie all eating disorders. It may be a shift in disorders over time. Social withdrawal as part of starvation is more frequently observed in patients with anorexia. Clinical perfectionism is also believed to be higher in anorexic patients as they ‘succeed’ in their attempts to ‘starve’. However, mood intolerance is less common among patients with anorexia. Core low self-esteem and interpersonal difficulties are present in both disorders to the same extent.

The transdiagnostic treatment

It is not said that these four mechanisms are always present in every patient, neither is it assumed that the mechanisms work simultaneously.

The treatment based on the extended version of cognitive behavioural theory is characterised by:

• Its broad application for all types of eating disorders.

• The specific diagnoses of the disorder is not important for the treatment per se. Rather it is based on the features detected as the maintaining factors for a dysfunction in the individual.

• No specific facilities or therapists are needed.

• 20 sessions are assumed to help in the majority of patients and 40 sessions are needed for more severe cases.

• A one-to-one basis.

It is based upon four stages:

1. Initial stage: (4 weeks) engaging, educating the patient, achieve maximal early behaviour change.

2. Stage two: (1 to 3 sessions) review of progress, identifying barriers, assessing presence of the four mechanisms.

3. Stage three: (longest part) revision of cognition and behaviour while addressing clinical perfectionism, core low self-esteem, mood intolerance, and interpersonal difficulties.

4. Final stage: just as in CBT, ensuring to keep working on the process of rehabilitation on their own.

Broader proposals

Shared distinctive features and a movement of patients between diagnostic states seem to be indicators for transdiagnostic processes that maintain either disorder.