2.1.1. What do we know about the causes of eating disorders?

While there are many theories regarding the causes of eating disorders, the evidence to date is weak for any one causal factor. There is some evidence suggesting roles of genetic, neurobiological and sociocultural factors though their specificity and generalisability are limited at present. The limitations of the research are due in part to the low prevalence rate of the disorders, making early screening for risk factors impractical. However, the time between onset of the disorders (which is not always a clear point) and identification of the disorders is often several years (due to issues such as control and shame), meaning that determining causality is very difficult. Consequently, there is a greater focus on the maintaining factors, which can be identified much more readily. These include the cognitive, emotional, physical and social consequences of malnutrition, binge eating, purging, etc., which have been built into models that have been tested in empirical studies and treatments.

2.1.2. The natural course of eating disorders

The majority of eating disorders have their origins in adolescence and young adulthood, though a substantial number of cases begin at younger or older ages. If left untreated (or if treated inadequately), the maintaining factors mean that many cases continue for decades, though severity can vary over time and there can be temporary periods of remission. Many cases will change from one diagnostic status to another, usually away from low-weight presentations (e.g., an individual whose diagnosis changes over several years from restrictive anorexia nervosa to binge/purge anorexia nervosa to bulimia nervosa).

2.1.3. Special issues regarding children with eating disorders

Children and adults can each have the full range of eating disorders (see following sections). However, there are important differences in how treatment should be focused at different age points relative to the development level of the person. First, because child cases are usually those that are identified earlier in the process, the patients are more commonly underweight. Second, while early intervention is to be encouraged at all ages, the long-term physical complications of malnutrition that are specific at this age (e.g., growth, pubertal delay, dental problems, osteoporosis, fertility problems) makes such early intervention critical in children with eating disorders. The role of the family in addressing the disorders tends to be emphasised in younger cases, while the focus is more commonly on the individual in adult cases.

2.1.4. The cultural context of eating disorders in Western societies

Eating disorders are found globally, though they have been identified for longer in Western cultures. It can be argued that this is a result of such societies placing stress on the value of specific body types, particularly among women. There is some evidence that encroaching ‘westernisation’ is followed by a greater level of eating disorders in ‘non-Western’ societies, as those values are spread via a range of media and individuals strive to fit to the newly incorporated standards.

It is also important to consider whether there are cultural differences within societies. While it is clear that females are more likely to experience eating disorders than males, there has been a noticeable increase in identification of men with eating disorders in recent years. There is also a greater prevalence among those in ‘at-risk’ professions where there is a focus on body shape and weight (e.g., athletes, dances, models). Despite this, there is no evidence that other differences (e.g., ethnicity; socioeconomic status; sexuality) make it more likely that a member of any one group will have an eating disorder. However, cultural factors do play one important role. For example, professionals are less likely to identify an eating disorder if the person does not fit the stereotype for such cases (e.g., non-Caucasian or male).

2.2.1. Anorexia nervosa

The prevalence of anorexia nervosa in young females in Western Europe and the US has been estimated to be approximately 0.3% (range = 0.2 – 0.8%) (van Hoeken et al., 2003). Incidence rates range from 4.2 to 12.6 per 100,000 person-years (Currin et al., 2005; Micali et al., 2013; Steinhausen and Jensen, 2015). The incidence of anorexia nervosa among males is lower, at 1 per 100,000 person-years (Currin 2005). Anorexia nervosa is relatively rare in children under 13 years, with a reported incidence rate of 1.1 per 100,000 person-years (Nicholls et al., 2011). It is also relatively rare among middle-aged and elderly women (Lapid et al., 2010) with an estimated lifetime prevalence in the UK of almost 4% (Micali et al., 2017). The incidence of anorexia nervosa, as identified by GPs, has remained stable over the past decade, with a peak age of onset of 15–19 years (Micali 2013).

Anorexia nervosa has the highest rate of mortality among all mental disorders. Its weighted crude mortality rate (CMR) is approximately 5.1 deaths per 1,000 person-years. The most common causes of death are suicide (20%) and cardiac complications (Arcelus et al., 2011).

2.2.2. Bulimia nervosa

There is a lack of epidemiological evidence specific to the UK context. In Western Europe and the US, the one-year prevalence of bulimia nervosa has been estimated to be approximately 1% in women and 0.1% in men (van Hoeken 2003), although the people in this study were predominantly under 35 years of age. Recent studies have also suggested that the prevalence of bulimia nervosa in men may be higher than previously thought (Hudson et al., 2007; Sweeting et al., 2015). Incidence studies suggest an increase in diagnoses in the 1980s and mid-1990s, followed by a decrease in incidence in the late 1990s (Currin 2005), with stability since that time (Micali 2013). The incidence of bulimia nervosa showed a similar pattern of increase and decrease over that time period, peaking at 12.2 per 100,000 person-years in 1993 but reducing to 6.6 per 100,000 in 2000 (Currin 2005). Age at identification also appears to be decreasing, currently sitting among 15 – 24-year-old females (Smink et al., 2012), though it is not clear whether this reflects earlier detection or earlier age of onset. Bulimia nervosa has a weighted crude mortality rate of 1.74 per 1,000 person years and an overall standardised mortality ratio of 1.93 (Arcelus 2011).

2.2.3. Binge eating disorder

The lifetime prevalence of BED in Europe has been estimated to be approximately 1.9% for women and 0.3% for men (Preti et al., 2009). Compared with the other eating disorders, BED is more common in males and older individuals. BED is commonly associated with obesity, which in turn is associated with increased risk of mortality.

2.2.4. Atypical eating disorders

Such cases are labelled as eating disorder not otherwise specified (EDNOS) or other specified feeding or eating disorder (OSFED) in different editions of the Diagnostic and Statistical Manual of Mental Disorders (DSM) (APA, 1994; APA, 2013). Atypical cases form the largest single category of eating disorders (Fairburn and Harrison, 2003). Lifetime prevalence of EDNOS in the US has been estimated to be around 4.8% in young people and 4.6% in adults (Le Grange et al., 2012). More cases have been identified in recent years (Micali 2013), from 17.7 per 100,000 in 2000 to 28.4 per 100,000 in 2009. Those authors showed that EDNOS is the most commonly diagnosed eating disorder in males (4.2 per 100,000) and its female to male ratio for EDNOS was 7.7:1 in 2009. It should be noted that due to the recent introduction of the OSFED category in DSM 5, the prevalence of OSFED is less clear.

Variation in existing provision

There is wide variation in how eating disorders are treated and managed in the NHS. This variation can be seen across the whole care pathway from the initial referral, through primary psychological services, outpatient child and young people mental health services (CAMHS), as well as across adult services. Some teams provide generic support, while others offer more specialist input. This variation is also applicable to inpatient services, with some service users being treated in specialist eating disorder units and others being admitted to generic mental health units.

Significant geographical inconsistencies exist, with different areas providing widely contrasting services. This pattern of geographical difference is likely to be influenced by variations in funding across the country, as well as differences in referral criteria to specialist services. For example, NHS England Specialised Commissioning has contracts with both NHS and private inpatient units, with admission criteria largely dependent on where the service user lives. Consequently, people can sometimes be admitted to units geographically distant from both their home and community-based services.

Primary and secondary care pathways

Most patients with eating or feeding symptoms initially present in primary care, though not necessarily with these symptoms as their presenting problem. The nature of an eating disorder and the inherent ambivalence (e.g., control issues, shame) often make it very unlikely that the individual with the eating disorder will seek help, and so treatment may initially be sought by a family member or carer, particularly in the case of children and young people. Clinicians working in primary care will have very different levels of experience, skill and confidence in diagnosing, assessing and managing such patients. Some primary care doctors and nurses lack the experience to offer the robust initial assessment that is needed to ensure that appropriate onward referral is made. Furthermore, referral pathways from primary care into secondary services will vary for adults, although these pathways are now being standardised for patients aged 18 and under. In some areas, much more specialised primary care assessment and triage services have developed in response to increasing demand from patients and link into very well developed secondary care pathways. Following an initial assessment GPs will consider referral to specialist secondary services where these are available locally. They will also consider medication, if relevant, and follow up as appropriate. Physical investigations may be carried out in primary care if indicated.

Due to the fact that many people see their dentists frequently, dentists may be the first professionals to recognise eating problems as a result of identifying patterns of dental erosion (Aranha et al., 2008). Recognition of the effects of eating disorders is taught by all dental schools in the UK. Dental treatment can affect outcomes and appearance is important for these patients. Current additive techniques with tooth coloured composite resins provide simple, aesthetic, effective and protective treatment.

Access pathways for children and young people

In relation to children and young people, there have historically been inconsistencies in service provision across the country, some young people being treated in generic CAMHS teams rather than specialist eating disorder teams. In areas where there are specialist services for younger patients, some will provide treatment and management of eating disorders up until the age of 18 years. In some areas, the treatment and management of 16 – 18-year-olds will be delivered within adult services, whilst a small number of specialist services take patients aged 14 years and over. In 2015, NHS England published a commissioning guide to access and waiting Times, designed to redress some of this variation in care for younger patients by setting standards for access and waiting times to receive an evidence based psychological intervention (NCCMH, 2015).

Very few age inclusive teams that cover the full period of biological maturation (12–25 years) exist across the country. Service access criteria related to age are likely to impact important aspects of care, such as the extent to which parents/family are involved and the level of responsibility the young person is encouraged to take. It is best practice for CAMHS and adult services to have a clear transition protocol thus enabling a smooth transition between services when required.

Access pathways for adults

Access to adult services tends to be either directly via primary care or through secondary adult mental health services. As in CAMHS, referral criteria vary, often influenced by funding and historical practice. In some areas, services will accept referrals of a wide range of eating disorder presentations, but in areas where funding is more limited, services may have strict referral criteria, such as a BMI cut-off or therapy only being offered to those within a specific BMI range.

A further transition issue is the care of University students with eating disorders, as they are often based at home for part of the year and at University for the remainder. Therefore, these individuals require particularly high levels of coordination between services (and with funders) to ensure that their access to care and their therapy is not compromised.

Treatment diversity

Waiting times for treatment vary significantly. Alongside offering out-patient treatment, some community services will also provide more intensive day-care treatment, but again there is significant variation across the country. Specialist in-patient treatment for children and young people, as well as adults, is currently funded by NHS England. In-patient beds tend to be accessed via specialist community services.

There is great variety in current therapeutic choices (interventions) offered and in the skill-set of the clinicians delivering these interventions. At times this can leave both patients and healthcare professionals in some confusion as to how best to manage these clinical cases. It is a clinical area in which a diverse range of therapies have evolved over the last few years, adding to the potential for challenging medical, nursing and psychotherapeutic decision-making. The Access and Waiting Times initiative (NHS England 2015) aims to address this variation in the type of therapy as well as the referral pathway. At present this only applies to those aged 18 and under.

Inpatient care

Inpatient care, particularly for anorexia nervosa, was central to the management of eating disorders in the twentieth century. However, there has been a move to more community-centred care with hospital care restricted to the patient group with severe medical risk and/or a failure to respond to outpatient care. The main goal of inpatient treatment is to reduce medical risk by improving nutrition. This usually involves meals supervised by nurses. Facilities with less than 24 hours per day care such as partial hospitalisation or day care are used as an alternative to inpatient care, or as the second phase in a form of stepped care. Inpatient care is less often used for bulimia nervosa unless comorbidity with problems such as diabetes increase the medical risk.

Clinical Practice

In in-patient care levels of anxiety are high before, during and after meals. This may be marked by intense emotional displays, but more often patients have a ‘poker face’ with restricted facial expression of emotions. This blocks an empathic reaction from staff who can become frustrated and hostile. On the other hand, if others recognise the terror associated with food, they may be drawn into accommodating the illness enabling eating disorder behaviours to persist. Thus, careful planning and supervision is needed to achieve a balance between avoidance and coercion. Eating is non-negotiable. On the other hand, the form and content of food-related activities can be individualised to a degree. Advance planning and review and a rule of no negotiations during meals themselves are helpful strategies.

Tube Feeding

Nasogastric (NG) feeding is used in in-patients settings and is recommended over other enteral routes or parenteral nutrition when nutrition cannot be taken orally. NG feeding is relatively common in children and young people with anorexia nervosa but not so often in adults in the UK, although the Care Quality Commission aims to ensure all units are equipped and competent to do it when needed. It is important that patients, parents and carers are involved and understand the rationale for its use as a way to provide adequate and safe quantities of calories where patients appear unable to do this orally. Conversely, efforts must be given to avoid either explicit or implicit punitive application.

The lower threshold for use in young people is multifactorial and includes the fact that the impact of malnutrition in young people can be more acute and have lasting consequences on growth and development. The law also puts emphasis on adults being responsible for the care of young people up to the age of 18, taking into consideration increasing autonomy and capacity. Additionally, there is evidence that early weight restoration has an impact on outcome, justifying an aggressive approach to refeeding in the early stages of the illness. However, randomised trials looking at how this weight gain is achieved (NG versus oral) have not been undertaken in young people. A case series of young people fed by NG tube found that, at follow up two thirds of patients thought the intervention had been necessary, while the remaining third still had negative views (Neiderman et al., 2001). A proportion of young people (and adults) want to be tube fed as it can be preferable not to feel responsible for eating (Neiderman 2001). Clinical practice varies widely on use of NG feeding in children and young people, with some units using it continuously (Kohn et al., 2011) and others only as a last resort (for example by offering meal support instead) (Couturier and Mahmood, 2009).

Rate of refeeding

There are existing guidelines on refeeding such as the NICE guideline on nutrition support for adults (NICE, 2006). There is now concern in the field that if these guidelines are applied to people with an eating disorder they may be underfed. Several studies have been examining this question (Madden et al., 2015; Redgrave et al., 2015). The only randomized controlled trial of refeeding to date found that young people randomized to high energy intake (1200 kilocalories versus 500 kilocalories) had greater weight gain than those on a more conservative regime, without a statistically significant increase in risk (O’Connor et al., 2016a). There is considerable variation in the amounts of starting calories internationally and between units.

Treatment Environment

For young people, the inpatient or day patient environments can be a place to practice family meals and develop a structure for mealtime management with staff support. Such environments may also provide time, space and motivation for psychological change to begin. Home leave is an important aspect of care, providing opportunities for skills to be put into practice. The value of inpatient care in those with severe and enduring anorexia nervosa is more questionable, other than as a life saving measure when appropriate.

It is challenging to develop a strong evidence base regarding interventions on inpatient and day patient settings, as randomisation to different forms of intervention within such settings can be problematic and it is difficult to find effects over and above those resulting from standard care.

Admission Criteria

There is no international agreement on the admission criteria for in-patient care and the thresholds specified in national guidelines vary. Healthcare settings also differ internationally; in some paediatrics/medical models of care predominate, in others eating disorders form part of generic mental health services, and yet others specialist eating disorder units are the norm. In part, admission criteria depend on the facilities available and the amount of risk they are able to manage. Patients with extreme medical risk and multiple organ failure are usually admitted to general medical hospitals. In the UK, the ‘Management of Really Sick Patients with Anorexia Nervosa’ (MARSIPAN) protocol has been developed to describe the care pathway for such cases, in both adults and children and young people, and to optimise the liaison between physical and psychiatric care (Royal College of Psychiatry, 2012; Royal College of Psychiatry, 2014).

Discharge Criteria

The traditional goal of inpatient care was to restore weight to normal. The underlying assumption was that normal physiology and eating habits would then resume. Indeed, low weight at discharge increases the likelihood of relapse and readmission. However, the outcome of inpatient care is confounded by many factors such as the level of motivation, and further randomised controlled trials are essential to interpret findings. Shorter periods of inpatient stay and lower discharge BMIs are part of current practice.

Aftercare

The relapse rates following a first admission to inpatient care are 20–30% rising to 50–75% for those with more than one admission (Lay et al., 2002; Steinhausen and Seidel, 1993; Strober et al., 1997). Psychological interventions for patients and/or carers delivered face-to-face or through various form of technology have been found to reduce the rate of relapse. On the other hand, dietary advice or medication appears to have no impact. A systematic review of the longer term follow up of inpatient/aftercare treatment in two RCTs (Eisler et al., 1997; Godart et al., 2012) have found that involving families in the post intensive treatment aftercare of young people improves outcomes. One pilot RCT has found that involving carers in the aftercare of adults improves outcomes (Hibbs et al., 2015; Magill et al., 2016).

UK resources

Beat (2015) has reported on the costs associated with eating disorders in the UK. Their calculation included three cost categories:

• treatment costs (including both NHS and private providers) amount to £8,850 per individual per annum (in likely 2011 prices);
• direct financial burden to those with an eating disorder and their carers (excluding any payments for private treatment) amount to £4,300 per annum;
• indirect financial burden on those with an eating disorder and their carers, resulting from disruption to education, employment and professional development amount to £10–15.4 thousand per annum (according to educational and employment status of the sufferer).

Thus, the cost to health service resources of the treatment element was £8,850 per individual per annum. However, that cost will be much higher for in-patients and lower for out-patients.

Using a broader basis for assessing treatment costs, including costs to the educational and voluntary sectors, Byford and colleagues (2007) showed that the cost per annum of treating young people was £26,738 in a specialist outpatient service and £34,531 in a specialist in-patient unit (in 2003/2004 prices). However, both were less expensive than treating them in general CAMHS services (annual cost of £40,794).

Comparison with resource use in other countries

Comparative resource costs are provided for other countries, with the provision that the baseline costs of care vary across countries, for example, the level of staffing and staff costs and the greater use of in-patient resources in some countries, reducing immediate comparability. In addition, the following figures need to be corrected upwards to allow for the year in which they were assessed.

• In Germany, the cost of a treatment episode was €5,251 for anorexia nervosa and €3,265 for bulimia nervosa (Haas et al., 2012) in likely 2011 Euros.
• In an earlier German study, the annual cost was €5,300 for anorexia nervosa and €1,300 for bulimia nervosa (Krauth and Buser, 2002) in likely 2001 Euros, indicating that the length of treatment episode for bulimia nervosa may have increased or become more hospital-based over the decade between the studies

Overall resource costs have been shown to be higher than the comparable costs for non-eating disordered individuals:

• Overall, in the US, those with eating disorders spent $1,869 per annum more on healthcare costs than those without eating disorders (Samnaliev et al., 2015) in likely 2014 US dollars.
• In the US, healthcare costs for eating disorders were substantially higher for eating disorders ($37,125 over five years) than for a non-disordered group ($13,725 over the same time period), though the figures for people with an eating disorder were similar to those for people with depression (Mitchell et al., 2009) in likely 2008 US dollars.
• In the US, one-year healthcare costs are higher for people with binge eating disorder than for those with EDNOS (by as much as $5,589) and higher than those for controls who do not have an eating disorder (by as much as $18,152) (Bellows et al., 2015) in likely 2014 US dollars.

Inpatient care is particularly costly. For example:

• In Germany, mean costs over three months of care for anorexia nervosa patients was costed at €5,866, but most of this accounted by the cost of hospitalisations (Stuhldreher et al., 2014) in likely 2014 prices.
• Health service costs in the US for acute inpatient care in a general hospital were $12,141 for anorexia nervosa and $8,697 for bulimia nervosa (O’Brien and Ward, 2003) in likely 2002 US dollars.
• Considering different eating disorders (Striegel-Moore et al., 2004), inpatient care has been shown to be considerably more expensive than outpatient care:

  • anorexia nervosa: $16,740 (inpatient) versus $2,242 (outpatient);
  • bulimia nervosa: $9,380 (inpatient) versus $1,848 (outpatient);
  • EDNOS: $12,748 (inpatient) versus $2,146 (outpatient); in likely 1999 US dollars.
• Among children and young people with eating disorders in the US, the mean cost of an inpatient stay (mean duration of 18.4 days) was $10,019 (Robergeau et al., 2006) in likely 2005 US dollars.
• In a further study of young people treated in the US, the annual cost of treatment was $33,105 (Lock et al., 2008) in likely 2007 US dollars. However, the medical element (inpatient and outpatient monitoring) accounted for 81% of this cost.
• Again in the US, Lock and colleagues (2003) costed a mean period of 23.2 days of inpatient treatment for young people with anorexia nervosa at $25,750 in likely 2002 US dollars.
• In 22 residential eating disorder treatment programmes (including people with anorexia nervosa and bulimia nervosa) in the US, the mean length of stay was 83 days and the mean cost per person was $79,348 (Frisch et al., 2006) in likely 2005 US dollars.

Non-health-service costs are also significant. For example:

• Disability payments to individuals with anorexia nervosa in British Columbia, Canada were calculated to be $101.7 million per year, which is approximately 30 times the cost of all tertiary care services of eating disorders in the province (Su and Birmingham, 2003) in likely 2002 Canadian dollars.

Additional resources

There are also substantial healthcare resource costs that are related to the use of non-eating disorder services. For example:

• In the US, people with binge eating disorder had higher generic healthcare costs ($1,379 in six months) than age- and gender-based norms (Grenon et al., 2010) in likely 2009 US dollars.
• In the US, substantial amounts of herbal and alternative medications were used, with an estimated cost of $33.88 per individual per month (Steffen et al., 2006) in likely 2005 US dollars.

Conclusion

To summarise, the health service costs per eating-disordered patient in the UK are approximately £8,850 per individual per annum year. This cost refers to people with an eating disorder, but does not distinguish across the type of eating disorder. However, the cost of anorexia nervosa treatment is likely to be higher than that of other eating disorders as this relatively small group of cases receives substantially more inpatient care. These figures are not directly comparable with those from other countries, though such figures do support the conclusion that eating disorders (in particular, anorexia nervosa) result in a substantial economic burden on healthcare resources. Efficient use of available healthcare resources will maximise the health benefit for people with eating disorders and can potentially reduce costs to the healthcare system as well as to society as a whole.