Researcher calls for rethink of diagnostic criteria for anorexia

Evelyn Lewin

14/12/2018 11:35:15 AM

One third of adolescents hospitalised with life-threatening anorexia nervosa are not underweight.

Patients with ‘atypical’ anorexia nervosa can suffer low blood pressure and deranged blood electrolytes without being underweight.
Patients with ‘atypical’ anorexia nervosa can suffer low blood pressure and deranged blood electrolytes without being underweight.

New research published in the Journal of Adolescent Health has found that 31% of Australian teen patients with anorexia nervosa had all the cognitive features and physical complications of the disease without being underweight.
The research consisted of retrospective and prospective studies of 171 patients aged 12–19 years who were hospitalised with anorexia nervosa. It found that 51 of the patients were ‘atypical’ in that they had significant eating disorder psychopathology, but were not underweight.
Lead researcher Melissa Whitelaw, who is an accredited practicing dietitian, said atypical anorexia nervosa was commonly perceived as less severe than ‘typical’ anorexia nervosa, in which a patient was significantly underweight.
However, her research showed the health consequences could be just as dangerous, with patients with atypical anorexia nervosa suffering low blood pressure and deranged blood electrolytes. Greater weight loss was associated with life-threateningly low pulse.
No complication of the condition was independently associated with being underweight, despite that being the ‘hallmark’ of anorexia.
The research found that in adolescents with restrictive eating disorders, total weight loss and recent weight loss were found to be better predictors of many physical complications than their weight on admission.
Consequently, Mrs Whitelaw believes it is time to change the current diagnostic criteria that state those with anorexia nervosa must be underweight.
‘What we are seeing now is that you can have a healthy body weight but be just as sick as someone with typical anorexia nervosa, including having the same thoughts about eating and food,’ she said.
‘We need to redefine anorexia because an increasing proportion of anorexia nervosa patients are atypical and more difficult to recognise. The definition should refer to weight loss, not just underweight.’
Dr Elizabeth Crouch, a GP with a special interest in eating disorders, agrees with Mrs Whitelaw.
‘I think loosening the actual criteria [of the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition: DSM-5] would be a good thing,’ she told newsGP.
In Dr Crouch’s experience, it is not uncommon to see patients with eating disorders such as anorexia nervosa who are not underweight. She believes diagnosing the condition based on body weight is ‘a very restrictive way of looking at it’.
Dr Crouch said sticking to a strict criteria for diagnosis can impact people’s ability to access treatment. Early intervention is optimal, she explained, as people with eating disorders can find it difficult to maintain awareness as the disease progresses.
‘[If] we have to wait until people meet criteria that are very strict before they can access services, they’re going to lose insight and the difficulty is that the time to engage them in therapy is going to be more difficult,’ she said.
‘We shouldn’t be the ambulance at the bottom of the cliff.
‘We really should be helping people if they have an issue … before they start to get more and more sick and unwell.’
Mrs Whitelaw is urging healthcare workers to pay attention to adolescent patients who are losing weight – regardless of whether they are underweight.
‘If adolescents lose weight, it doesn’t matter what weight they are. A health professional should monitor them to check that weight loss is appropriate and if so, that it is done gradually,’ she said.
‘They should also monitor the adolescent’s dietary intake and relationship with food and exercise for signs the patient is spiralling into an eating disorder. Following large amounts of weight loss, careful medical assessment is also recommended.’
Given it is normal for adolescents to maintain or gain weight as they develop, Dr Crouch believes ‘any weight loss is something to take seriously’.
‘The face of eating disorders is changing against a backdrop of increasing prevalence of overweight and obesity,’ Mrs Whitelaw said.
‘Families, teachers, sports coaches and others interacting with young people should not delay seeking help for adolescents with worrying eating patterns if they have lost weight, even if they are not underweight.’
According to the DSM-5, a patient must display a persistent restriction of energy intake leading to significantly low body weight to be diagnosed with anorexia nervosa, among other diagnostic criteria.
Other diagnostic criteria include either an intense fear of gaining weight or becoming fat, or persistent behaviour that interferes with weight gain (even though significantly low weight), along with disturbance in the way one's body weight or shape is experienced, undue influence of body shape and weight on self-evaluation, or persistent lack of recognition of the seriousness of the current low body weight.
Mrs Whitelaw said people understand the need for a severely underweight patient to gain weight, but that often it is a shock to individuals and families when someone within or above the healthy weight range are told they need to gain weight.

adolescents anorexia nervosa diagnostic criteria eating disorder underweight

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