By Sarah Ford, InPsych feature writer

EATING disorders suffer from a poor image. Their public picture is typically an emaciated, young female starving herself in pursuit of the thin ideal. Meanwhile many psychologists perceive the area as a particularly challenging one to work in, a notion that is partly driven by difficulties in treating the sometimes fatal disorder, anorexia nervosa.

In reality there are a number of eating disorders that affect women and men of all ages and sizes. Understanding these disorders and how to treat them is complex - they are caused by a broad range of biological, environmental and psychological factors.

The past decade has seen a high level of research into eating disorders conducted in Australia and local psychologists are internationally regarded for their efforts. "For the size of the country, we have an unusually large number of people who are excellent researchers in this area," says Dr Justin Kenardy, an Associate Professor in the School of Psychology at the University of Queensland in Brisbane.

Much of Justin's research has focused on binge eating disorder (BED), which is characterised by recurrent episodes of excessive eating, and is strongly associated with obesity. It affects men and women in roughly equal proportions across a range of ages, with some not developing it until their sixties.

BED affects around 2% of the population and is included in the group classified as Eating Disorders Not Otherwise Specified (EDNOS) in the DSM-IV. This is a catch-all category for various, clinically significant eating disorders that do not fulfil the diagnostic criteria established for the better-known disorders of anorexia nervosa and bulimia nervosa.

Anorexia is characterised by a refusal to maintain a minimally normal body weight and an intense fear of gaining weight. It affects around 0.5%-1% of females. Bulimia is characterised by recurrent binge eating followed by compensatory behaviours, such as vomiting, dieting and/or taking laxatives. It occurs in 1%-3%of women. A distorted perception of body weight and shape is a key feature of both disorders, which usually manifest in adolescence. Males only account for about one in ten cases of anorexia and bulimia.

Spotlight on anorexia
Despite the lower prevalence of anorexia, it is the eating disorder that commands the media spotlight and captures the public's attention. Justin suggests that anorexia attracts more publicity than BED because the media prefers images of emaciated young girls rather than obese people.

Added to these social biases towards thinness and youth is the misperception that overeating is not a psychological problem. "Anorexia sufferers are typically young girls who have the whole of their life ahead of them," Justin says, "but binge eaters are considered to have just lost will power and brought the disorder upon themselves."

Anorexia also receives attention for its high fatality rate - more than 10% of people with the disorder die. While not detracting from the seriousness of this, there seems to be little recognition that binge eating can also be fatal, Justin says.

He says there is a strong association between BED and obesity, with people graduating from binge eating to global over-eating over time. "An individual who binge eats has discreet periods of eating and non-eating and what happens is that those discreet periods disappear and it becomes continuous," he says.

Justin suggests that BED occurs equally in both genders because it is driven by universal concerns such as interpersonal factors and distress. "There is some indication that the types of aversive emotions that trigger binge eating differ for men and women," he says, "but the process is the same."

In comparison, anorexia and bulimia are more common in women because these disorders tend to be driven by body image concerns.

The nature of emotional eating
Justin has studied the nature of emotional eating and its relationship to clinical eating disorders. One theory underlying binge eating is that people who use over-eating as a way of managing their affect are trying to resolve problems for which they see no other available or desirable strategy.

People who engage in emotional eating struggle with issues such as over-attending to other people's needs or dealing with interpersonal conflict. "Sometimes people use emotional eating as a way of asserting themselves," Justin says. "It seems weird but an individual might overeat in a rebellious way. They eat almost as an aggressive act, which is maladaptive."

Research by Justin and colleagues has found an interesting twist to the emotional eating theory. Clinical levels of emotional eating are usually triggered by a desire to reduce negative affect, but the ultimate effect is a post-binge guilt that leaves people feeling bad after eating.

According to this Trade-off Theory (Kenardy et al., 1996) people who binge eat are willing to feel one kind of bad over another. "Evidence shows people who engage in this behaviour would far prefer to feel guilty, than depressed or angry," Justin says.

The role of genetic and environmental factors
In recent years research on anorexia and bulimia has broadened from focusing on individual factors, such as perfectionism, to consider the interplay of social, psychological and biological issues.

Dr Tracey Wade, a Senior Lecturer in the School of Psychology at Flinders University in Adelaide, has been teasing out the contribution of genetic and environmental factors to eating disorders. Tracey and colleagues conducted twin studies on disordered eating using three waves of data from the Australian Twin Registry and found that 59% of variance is genetic and 41% is non-shared environment related (Wade et al., 1999).

"We also found that when you start looking at particular components of eating disorders, like weight concerns, they are actually purely influenced by the environment", Tracey says. "It is a complex situation."

She is continuing her twin research to investigate environments that increase vulnerability to developing eating disorders. Findings to date are that conflict between parents as their twins are growing up confers an independent risk of developing bulimia on top of the genetic risk. In addition, increased amounts of disordered eating behaviours are associated with increased reports of parental criticisms, and higher levels of psychopathology.

Tracey says disordered eating behaviours are sometimes measured instead of assigning specific eating disorder diagnoses because the diagnoses exclude many people who have significant eating problems. The DSM-IV produces "an artificial cut-off point", she says. "There is agreement that it needs to be changed." For example, a diagnosis of bulimia nervosa requires the binge/purge cycle to occur at least twice weekly over three months. But twin studies show once a week seems to be a more meaningful threshold, she says.

Another instance is the requirement of amenorrhea, the ceasing of menstruation, for an anorexia diagnosis, despite evidence that many women continue to get their period while meeting all the other criteria. "That may be because they are on the pill," Tracey says. "But it also may be because the body is not that predictable - you can be underweight and still get your period."

Treatment options
The treatment of eating disorders varies with the type of illness. Cognitive behavioural therapy (CBT) is an effective treatment for BED, and interpersonal therapy can be useful if interpersonal issues are related to the maintenance of the disorder. The initial problem is recognising the disorder and eliciting an admission to the secretive act of bingeing.

Furthermore, although the psychopathology associated with BED is generally less severe than that related to bulimia and anorexia, the lack of recognition of BED as a psychological problem is a barrier to obtaining treatment.

Like BED, bulimia is largely a hidden illness involving secret bingeing and purging. Detection is also difficult because people with bulimia generally maintain a normal weight.

Tracey says these factors lead to people with bulimia typically not entering treatment until about five years after developing the disorder, by which time the illness is ingrained and far harder for psychologists to treat. "Research suggests the longer the eating disorder is there, the worse people do in treatment", she says. "Some of them can't remember what life was like before bulimia."

Another barrier is that sufferers have often tried a number of treatments that haven't worked so they arrive feeling hopeless and despondent, she says. "But 50-60% of people with bulimia respond well to CBT, it is just that that message is not getting out to the public."

Compared with bulimia, the weight loss associated with anorexia often means the illness is detected earlier. However, anorexia has proven to be the most difficult of the eating disorders to treat and to date no specific treatment modality has been found effective.

Tracey says anorexia is such a challenging disorder because people do not want help. "People with anorexia are actually proud of the problem," she says. "This is something they have worked hard to get and they see is it as an achievement. It makes them special and in control, and is a solution to their problem."

However, there are good reasons for providing caring and sensitive psychological treatment for people with anorexia, according to Professor Susan Paxton from the School of Psychological Science at La Trobe University in Melbourne. "There is evidence that suggests support for combined and flexible treatment in which the patients needs are really listened to," she says.

All treatments should emphasise weight gain, partly because of the high mortality rate associated with the illness. Treatment should also take a team-based approach that includes medical, psychological and family support.

The challenge of prevention
Susan has been researching eating disorders for more than 15 years and has focused particularly on the area of prevention. Much of her work is on identifying risk factors for anorexia and bulimia to guide interventions and prevention programs, which in the past have lacked an evidence base. "It was done on an intuitive basis and the programs were not particularly successful," she says.

The past decade has seen the identification of more explicit factors, but the development of effective prevention interventions remains a fair way off, Susan says. This is partly because finding causal risk factors is particularly challenging in the area of eating disorders.

Research has identified concurrent problems, such as an association between low self-esteem and body image problems, but it is not clear whether these develop simultaneously or if one develops before the other. "Some things we do know are that body image problems are a risk factor for eating disorders," Susan says. "There is also strong support for the notion that dieting and extreme weight loss behaviours are risk factors for developing eating disorders."

So far targeted interventions aimed at people who already have some risk factors, such as body image problems and subclinical eating disorders, have proven more successful than global prevention programs provided at schools to females in early adolescence.

These interventions encompass motivations for change, strategies for normalising eating, and challenging social factors such as the value placed on thinness. One such program is being developed for the internet and results so far show that internet delivery is equally as successful as group-based therapy.

Susan says that for prevention to be effective, efforts need to be broadened. "Rather than thinking there is one point at which we have to offer intervention, we need different styles that stress different things at different times," Susan says. Effective and long-term interventions also rely on changing social attitudes to weight and body shapes.

Most prevention programs focus on building individual coping skills, which can be difficult to put into practice in a harsh social environment. "You can give someone these coping skills, but when you send them into a school environment where they are harassed for their weight and shape, good luck to you," Susan says, adding that schools should have policies on weight and shape teasing, which is essentially a form of bullying.

Australian society has a long way to go in accepting diversity in weight and shape, but Susan is optimistic that this can be achieved. She says that a growing acceptance of ethnic diversity in recent years shows that entrenched attitudes can change.

Kenardy, J., Arnow, B., & Agras, W. S. (1996). The aversiveness of specific emotional states associated with binge-eating in obese subjects. Australian & New Zealand Journal of Psychiatry, 30 , 839-844.

Wade, T., Martin, N.G., Neale, M.C., Tiggemann, M., Treloar, S.A., Bucholz,
K.K., Madden, P.A.F. & Heath, A.C. (1999). The structure of genetic and environmental risk factors for three measures of disordered eating. Psychological Medicine, 29 , 925-934.

See also: Understanding and managing eating disorders: An APS Tip Sheet