Chapter 32

Nutrition in mental health


Pharmacotherapy in mental health

Who can contribute to nutritional care in mental health?

Nutrition in specific mental health conditions

Developmental disorders

Eating disorders


Mental Capacity Act (MCA) 2005


Nutrition interacts with and influences mental health in a comparable way to physical health: a ‘healthy and varied diet’ can help promote mental wellbeing while an inadequate or excessive intake of food or specific nutrients can have a detrimental effect on mental health (Fig. 32.1). The duration and impact of nutritional effects vary depending on the life stage.


Fig. 32.1Relationship between wellbeing and nutritional status.

The Community Mental Health Survey (2018) reports that one in six adults has experiences a mental health condition in any given year. The interrelationship between mental health and nutrition includes a diverse range of topics ranging from those close to ‘normal’ healthy behaviour to the ‘extremes’ of mental ill health (see Table 32.1).

Table 32.1 Relationship between mood and eating*

Mood disorder and symptoms Potential nutrition consequences
Loss of appetite
Anhedonia, apathy, and disinterest in food
Altered sleep patterns, inadequate or excessive sleeping, including during the day
Tiredness—unable to cook
Loss of thirst sensation
Food craving/erratic eating habits
Comfort eating
Inadequate/inappropriate intake
Compromised nutritional status
Weight loss/gain
Tiredness/lack of concentration
Restlessness/hyperactivity ↑ Energy expenditure
Dry mouth Inadequate/excessive intake
Nausea, vomiting, diarrhoea Difficulty chewing and swallowing
Loss of appetite Compromised nutritional status
Food refusal Weight loss/gain
Comfort eating Tiredness/lack of concentration

* Note. Many of the nutritional consequences will contribute to the symptoms and potentially exacerbate them, e.g. tiredness in depression is associated with poor food intake → inadequate ingestion of energy and nutrients → further tiredness.

Pharmacotherapy in mental health

Drugs used in treating mental health problems may influence food intake and/or nutritional status. It should not be assumed that every patient taking medication will experience any or all of the side effects associated with specific drugs. When side effects arise, they are sometimes managed by adjusting the dose or changing prescription to a similar preparation that may be better tolerated. However, as some pharmacotherapy is long-term, e.g. taken for many years, there may be nutritional implications that require intervention (see Box 32.1).

Box 32.1 Examples of possible nutrition-related side effects associated with selected drugs used to treat mental illness


Tricyclic antidepressants, e.g. dosulepin, → dry mouth, sour metallic taste, constipation.

Selective serotonin re-uptake inhibitors (SSRIs) (5-hydroxy-tryptamine, 5-HT), e.g. fluoxetine, → dose-related side effects including diarrhoea, constipation, dyspepsia, abdominal pain, nausea, vomiting.

Monoamine oxidase inhibitors (MAOI), e.g. phenelzine, → patients taking these drugs should avoid foods containing high levels of tyramine, e.g. mature cheese, yeast extracts, soya bean products, pickled herring, and certain wines (see image…… Chapter 38, ‘Drug–nutrient interactions’.


Atypical antipsychotics, e.g. clozapine, olanzapine, → ↑ appetite, ↓ satiety, weight gain, hyperglycaemia, diabetes, dyslipidaemia (hypercholesterolaemia; hypertriglyceridaemia), drowsiness, dry mouth, constipation. Clozapine side effects include hypersalivation, impairment of intestinal peristalsis, including constipation, intestinal obstruction, faecal impaction, and paralytic ileus (including fatal cases) reported.

Thioxanthenes, e.g. flupentixol decanoate (used as depot injection), → ↑ appetite, weight gain, hyperglycaemia, dry mouth, constipation, drowsiness.

Mood stabilizers

Lithium salts, e.g. lithium carbonate, → nausea, dry mouth, dysgeusia, metallic taste (~ mild, controlled by adjusting dose); electrolyte imbalance: serum electrolytes must be checked (see image…… Chapter 38, ‘Drug–nutrient interactions’), oedema, weight changes, including weight gain.


Sodium valproate → sleepiness, increased appetite and weight gain, nausea.

Carbamazepine → tiredness, abdominal pain, nausea, diarrhoea, constipation.

Barbiturates, e.g. phenobarbital*, → ↓ vitamin D levels, ↓ folate levels; e.g. phenytoin* → ↓ vitamin D absorption, ↑ turnover, and ↓ absorption of folate

* No longer first choice of treatment but many patients continue to take it.

Who can contribute to nutritional care in mental health?

The vast majority of people with mental health problems live in the community, some autonomously and others requiring considerable support. Obtaining, preparing, and eating a well-balanced diet can be a challenge, and poor diet can exacerbate both short-term symptoms and the risk of chronic health problems associated with mental illness. It is well-documented that people with serious mental illness (SMI), including schizophrenia, bipolar disorder, and major depression, die 10-15 years earlier than the general population. This is largely a result of cardiovascular disease, including heart disease, heart attack, and stroke. A meta-analysis1 of SMI and cardiovascular disease, which included >3.2 million patients and >113 million people from the general population, reported that the risk of dying from cardiovascular disease was 85% higher in people with SMI than people of a similar age in the general population. Underlying causes may be multiple and include long-term antipsychotic use, adverse lifestyle choices such as smoking, poor diet, and physical inactivity and obesity.

In addition to family, carers, health professionals in primary care, and the community mental health team should be aware of nutritional risk and needs and plan care to manage nutritional concerns. Health professionals should receive training in up-to-date evidenced-based healthy eating and use a motivational approach and appropriate goal setting to help ensure that people with mental illness are given the best support possible with regards to their nutritional care. Dietitians are well-placed to guide other healthcare professionals and support workers with appropriate nutrition training and use of supporting resources to optimize their clients’ nutritional status. Referral to dietetic services is required for therapeutic dietary management of physical health co-morbidities, e.g. undernutrition, nutritional deficiencies (i.e. anaemia), overweight, obesity, diabetes, dyslipidaemia, and metabolic syndrome. In addition to considering the health benefits associated with the nutrients supplied by food, the pleasure of eating and the empowerment associated with preparing an edible meal can also make a valuable contribution. Occupational therapists are trained to assess life skills and to provide support with budgeting, shopping and cooking.

Nutrition in specific mental health conditions


Depression, or major depressive disorder, can be termed mild, moderate, or severe and may include feelings of anxiety. A person may comfort eat, which can lead to unhealthy weight gain or they may experience a loss of appetite with associated weight loss. When severely depressed, most people eat and drink poorly and are at risk of weight loss, becoming underweight, undernourished, and at risk of dehydration.

Low levels of neurotransmitters, e.g. serotonin, dopamine, noradrenaline, and -amino butyric acid (GABA), are observed in depression. Dietary sources of neurotransmitter-precursors, e.g. tryptophan, tyrosine, and phenylalanine may facilitate transmitter production with antidepressant effects. Systematic review2 indicates that supplements of 5-hydroxy tryptophan or tryptophan are better than placebos at alleviating depression, but insufficient evidence is available to recommend supplementation. Eating a ‘normal’ varied diet will provide physiological doses.

Omega-3 fatty acids may also play a role in neurotransmission via their conversion into prostaglandins and leukotrienes or through affecting signal transduction in brain cells. A meta-analysis3 has found evidence of benefit from omega-3 supplementation (daily doses ~0.1–6.0 g of n-3) in people diagnosed with depression. The benefits seem greater when supplementing higher doses of eicosapentaenoic acid (EPA) and when given as an adjunct therapy together with antidepressants. High doses of EPA will require use of omega-3 supplements without vitamin A and D added to avoid potential toxic intakes of these vitamins.

People with depression are more likely to have a ↓ intake and ↓ plasma markers of B vitamins. This may be a consequence of poor intake 2° to depressed appetite or co-morbidities rather than causative. Intervention studies are required to identify any potential benefit from supplements.

Existing evidence suggests that a combination of healthful dietary practices may reduce the risk of developing depression.4

An RCT of an adjunctive dietary intervention was used in treatment of moderate to severe depression using healthy eating guidelines and the Mediterranean diet. The dietary support group showed significantly greater improvement in depression symptoms than the control group and 32% achieved remission compared to 8% in the controls.5

Bipolar affective disorder

Bipolar is a complex psychiatric disorder usually treated with mood-stabilizing medication.

Omega-3 fatty acids play a key role in maintaining ‘fluidity’ of cell membranes, which influences neurotransmitter receptor function. Addressing relative depletion of omega-3s has been investigated as a potential treatment for bipolar disorder. Systematic review6 of clinical trials has indicated that omega-3 supplementation is safe and may be useful as adjunctive therapy for depressive but not for manic symptoms. Further studies are required before recommendations can be made.

A number of studies have investigated the effects of a range of water-soluble vitamins and amino acid supplements in bipolar disorder but without definitive evidence.


Patients with schizophrenia usually suffer from hallucinations, paranoia, delusions, and malfunctioning speech or thought.

Impaired amino acid metabolism, and specifically reduced serotonin synthesis, has been associated with the pathophysiology. Limited evidence indicates that amino acid supplements may reduce some schizophrenic symptoms without adverse effects.

Several studies have investigated the effects of omega-3 fatty acids in patients with schizophrenia, but systematic review7 of these has concluded that there is still insufficient good quality and independent evidence on which to base recommendations for supplementation.

Patients with psychotic disorders, including schizophrenia, have significantly lower levels of vitamin D compared to healthy controls with >50% deficient in vitamin D. Research findings suggest an association between vitamin D and psychotic disorders. However, the relevance of this deficiency remains unclear.8

Weight gain is associated with antipsychotic drugs prescribed for schizophrenia (see image this chapter ‘Pharmacotherapy in mental health’. NICE guidance9,10 recommends that nutritional assessment, including weight, waist circumference, diet, and physical activity, should be evaluated before commencing antipsychotic medication. NICE endorses the Lester UK Adaptation: Positive Cardiometabolic Health Resource developed by the Royal College of Psychiatrists, which is an intervention framework for people experiencing psychosis and schizophrenia.11 It highlights the need to not only screen for cardiometabolic risk but also to intervene and monitor to manage identified risks where indicated.

Constipation is a common and notable side effect 2° to antipsychotic use and is often unreported by patients unless prompted. Severity can range from mild constipation to fatal bowel obstruction. Constipation has been found in up to 80% of patients taking clozapine and 50% of patients taking other antipsychotics.12

Obsessive compulsive disorder (OCD)

OCD is an anxiety disorder and a common mental health condition. About 1.2% of the population have OCD at some point in their lives. It is estimated that there are ~750,000 people living with OCD at any one time in the UK, with half being categorized as severe cases. OCD affects men, women, and children, and can develop at any age.

A person with OCD experiences re-occurring obsessive thoughts, which can be distressing and cause the person to feel anxious. These are followed by related compulsive behaviours to try to manage these thoughts and reduce anxiety levels. These repetitive behaviours can become time-consuming and all-encompassing, and adversely affect the life of the sufferer and their loved ones.

In general, a person’s OCD will fall into one of the four main categories:


contamination/mental contamination;


ruminations/intrusive thoughts.

Nutritional impact of OCD

Underweight, undernutrition, and specific nutritional deficiencies can develop e.g. anaemia because of low iron, folate, and/or vitamin B12. This can result from difficulties obtaining food, i.e. going out shopping, food handling, preparation, and cooking (because of contamination concerns, rituals involving preparing food); rituals around eating are time-consuming and take priority over eating; avoidance of foods considered at risk of contamination or only consuming pre-packaged/sealed items drinks.

Complaints of gastrointestinal (GI) disturbance are likely to be associated with anxiety but can include diagnosis of irritable bowel syndrome; may lead to avoiding many foods fearing an adverse gut reaction leading to inadequate nutrition.

Co-morbid conditions can add additional nutritional challenges, i.e. eating disorders (restricting calories and food variety), depression (loss of appetite or comfort eating which can lead to overweight), and autistic spectrum disorder (limited array of foods eaten).

Treatment of OCD

Cognitive behavioural therapy (CBT) with exposure and response prevention.

Selective serotonin re-uptake inhibitors (SSRIs) provide effective pharmacological treatment of OCD. Therefore, in theory, foods which ↑ serotonin levels may also provide some benefit. There is no evidence to support this at present.

NICE guidance for OCD includes body dysmorphic disorder but does not refer to diet, nutrition, or food.13

Developmental disorders

Autism spectrum disorders

There are around 700,000 people on the autistic spectrum in the UK which is >1 in 100. It is diagnosed in more men than women.

People with autism spectrum disorders (ASD) can have an intellectual ability ranging from a severe learning disability to being academically ‘mainstream’; ~10% may also have special skills or abilities. Asperger’s syndrome is used to describe those with ASD who have an ability to function at a higher level. The characteristics of the conditions vary between individuals and with time, but can be summarized as:

difficulties with communication;

difficulties with social interaction;

difficulties with behaviour, interests, and activities.

Common co-morbidities include anxiety disorders, OCD, depression, GI disorders, sleep disorders, epilepsy, other neurological conditions, and allergies.


The exact cause of ASD is unknown, but a combination of genetic and environmental factors is thought to contribute to changes in brain development. It is unknown whether nutrition is causally implicated.

Common eating/food-related challenges in ASD

Mealtimes can be stressful because of hypersensitivity to noise, smells, or bright lights. Eating with others may be difficult for some, whereas others may find company at mealtimes helpful. Eating with the TV or radio on, and having set eating times and visual timetables can be helpful.

Eating a very limited range of foods can potentially lead to nutritional deficiencies and, in young people, to poor bone health and faltering growth. Food colour may influence its acceptability.

Foods which are predictably the same, e.g. baked beans, are commonly selected and choices may be brand-specific. Some foods are rejected because of their texture or serving with sauce. There may be ‘rules’ around eating, e.g. different foods must not touch on the plate.

Sensitive, graded exposure to different foods as well as treatment for related anxiety disorders affecting eating can be helpful.

Adverse gut symptoms such as constipation, diarrhoea, and stomach bloating may be experienced. Promoting high fibre foods, wholegrains, fruits and vegetables, drinking enough fluid, and being active can help.

Nutrition as treatment

Diet has been investigated as a possible treatment of ASD, particularly as nutritional status plays a vital role in normal brain development.14

Micronutrient supplementation: the potential benefits of vitamin B6 and magnesium supplements have been investigated in 33 trials. However, systematic review15 has concluded that these do not provide sufficient evidence on which to base recommendations and that further large, well-designed studies are needed.

Diets focusing on possible GI co-morbidity: links between GI tract symptoms and autism have led to evaluation of diets that might alleviate these including gluten- and casein-free diets and food elimination diets. Although there is some evidence16,17 to support a link between GI epithelial changes and altered immune response in ASD, the dietary benefits are predominantly anecdotal or from small or methodologically limited studies. NICE guidance recommends that exclusion diets, e.g. gluten- or casein-free, should not be used in autism.18 This is important because some people with ASD may already eat a limited range of foods so further restricting their diet potentially increases the risk of nutritional deficiencies, which could lead to severe weight loss and, in young people, adversely affect growth.

Omega-3 fatty acids: on the basis of their role in brain development and contribution to cell membrane integrity, >100 studies have investigated the role of omega-3s in ASD. However, on systematic review,19 this number was reduced to one randomized controlled trial that showed a small, but non-significant improvement associated with ~1.5 g/day over 6 weeks. NICE guidance recommends that omega-3 fatty acids are not used to manage sleep problems in autism.18

Further reading

Dietitians in Autism: image……

Food and Behaviour Research: image……

National Autistic Society: image……

Research Autism: image……

Attention deficit hyperactivity disorder (ADHD)

ADHD, or hyperkinetic disorder, is a syndrome characterized by hyperactivity, impulsivity, and inattention. People with ADHD may exhibit all of these symptoms or predominantly more of one and less of another. Symptoms vary in severity and only those with significant impairment meet criteria for a diagnosis of ADHD. Symptoms of ADHD can overlap with symptoms of other related disorders.


The exact cause of ADHD is unclear but a combination of genetic and environmental factors is thought to contribute to changes in brain development. High coffee intake in utero has been suggested as a contributory cause, but epidemiological studies have not identified this as an independent risk factor.

Nutrition as treatment

The role of diet has been investigated as a possible treatment of ADHD with little success:

Artificial colouring and additives: many studies have investigated the benefits of eliminating these from the diet. Current guidance recommends that this should not be a routine treatment.20 However, clinical assessment should include questions about food and drink and possible links to behaviour. If these are reported, an intake/behaviour diary should be kept, and then, if necessary, a referral made to a dietitian. Further dietary management, e.g. specific dietary elimination, should be jointly managed by a dietitian, mental health specialist/paediatrician, and patient/carer and young person.

Omega-3 (and other) fatty acids: have been investigated in ADHD because of their role in brain development and contribution to cell membrane integrity. Although some studies have reported improvements in behaviour, the consensus,21 is that there remains insufficient evidence to support supplementation and that further well-designed and long-term studies are needed.

Weight loss or poor weight gain: may arise in adults and children with ADHD if food intake is poor, hyperactivity results in energy expenditure exceeding intake or in association with some medication, e.g. methylphenidate, atomoxetine, or dexamfetamine. Routine monitoring of weight and, in children, plotting height, weight, and BMI on growth charts is required. Taking medication with or after food or changing mealtime to avoid peak drug-action may also help.

Eating disorders

Defined as persistent disturbance of eating (± behaviour) that impairs physical health or psychosocial functioning or both and that is not 2° to any other medical or psychiatric disorder.

Includes anorexia nervosa (AN), binge eating disorder (BED), and bulimia nervosa (BN).

Individuals who do not fall within strict diagnostic criteria are described as having other specified feeding or eating disorder (OSFED) and should be treated according to the guidelines that their condition most closely resembles.

Pathogenesis includes

Genetic factors: estimated hereditability 50–83%.

Biological factors: starvation impacts directly on brain and is associated with behavioural and psychosocial impairment. Complex integration of appetite control, motivation to seek food and eat, and self-regulation may also contribute.

Environmental factors: may include events from conception onwards (stress in pregnancy, prenatal complications, prematurity) to societal pressures and concepts of ‘fatness’ and ‘thinness’.

Statistics for eating disorders

BEAT,22 the UK’s eating disorders charity, estimates that ~1.25 million people suffer from eating disorders in the UK and 20% of these are male. The age group most likely to be affected by an eating disorder is those aged 14-25 years, while 1 in 100 women aged 15-30 years are affected by anorexia

General principles of care23

Improving access to services for all people regardless of background and especially where stigma or shame may deter people from seeking help.

Optimizing communication, including with family members where appropriate, but recognizing the need for confidentiality and consent. Show empathy, compassion, and respect, and being sensitive when discussing a person’s weight and appearance.

Providing good information and support including assessing the impact on home, education, work, and the wider social environment including the Internet and social media.

Co-ordinating care between health professionals, different services, and in different settings where staff should be appropriately trained to work with the relevant age group.

Identification and assessment

People with eating disorders should be assessed and receive treatment at the earliest opportunity. Those with or at risk of severe emaciation, should be prioritised. A screening tool alone is not recommended as a sole method of determining whether or not people have an eating disorder. Do not use single measures such as BMI or duration of illness to determine whether to offer treatment for an eating disorder.

When assessing for an eating disorder or deciding whether to refer people for assessment, take into account any of the following:

Unusually low or high BMI or body weight for their age

Rapid weight loss

Dieting or restrictive eating practices when underweight

Disproportionate concern about their weight or shape

Family or carers reporting a change in eating behaviour

Social withdrawal, particularly from situations that involve food

Other mental health concerns e.g. depression, anxiety, self-harm, OCD

Problems managing a chronic illness that affects diet, such as diabetes or coeliac disease

Menstrual or other endocrine disturbances, or unexplained GI symptoms

Physical signs of:

malnutrition, including poor circulation, dizziness, palpitations, fainting, or pallor

compensatory behaviours, including laxative or diet pill misuse, vomiting, or excessive exercise

Abdominal pain that is associated with vomiting or restrictions in diet and that cannot be fully explained by a medical condition

Unexplained electrolyte imbalance or hypoglycaemia

Atypical dental wear (such as erosion)

Taking part in activities associated with a high risk of eating disorders e.g. professional sport, dance, fashion, or modelling.

In addition, be aware in children and young people an eating disorder may also present with faltering growth or delayed puberty.

▶ If an eating disorder is suspected after an initial assessment, refer immediately to a community-based, age-appropriate eating disorder service for further assessment or treatment.

Anorexia nervosa

ICD-10 descriptor: AN is characterized by deliberate weight loss, induced and sustained by the patient. It occurs most commonly in adolescent girls and young women, but adolescent boys and young men may also be affected, as may children who are approaching puberty and older women. It is associated with a specific psychopathology whereby a dread of fatness and flabbiness of body contour persists as an intrusive, overvalued idea, and the patients impose a low weight threshold on themselves. There is usually undernutrition of varying severity with secondary endocrine and metabolic changes and disturbances of bodily function. The symptoms include restricted dietary calories and variety, excessive exercise, micro-exercising, purging by self-induced vomiting, use of laxatives, diuretics, diet pills, and appetite suppressants, including amphetamines. The lifetime prevalence is 0.9% for women and 0.3% for men.


Support should:

include psychoeducation about the disorder;

include monitoring of weight, mental, and physical health, and any risk factors;

be multi-disciplinary and co-ordinated between services;

involve the person’s family members or carers if appropriate.

When treating AN, be aware that:

helping people to reach a healthy body weight or BMI for their age is a key goal;

weight gain is key in supporting other psychological, physical, and quality of life changes that are needed for improvement or recovery.

When weighing people with AN, consider sharing the results with them and family members or carers if appropriate.

Psychological treatment in AN

NICE guidelines23 define approaches for adults and for children and young adults. For adults, these include individual eating disorder focused cognitive behavioural therapy (CBT-ED), the Maudsley Anorexia Nervosa Treatment for Adults (MANTRA), and specialist supportive clinical management. For children and young people, consider AN-focused family therapy delivered as a single-family therapy or combined with multi-family therapy. If AN-focused family therapy is unacceptable, contraindicated, or ineffective, consider individual CBT-ED or adolescent-focused psychotherapy for anorexia nervosa.

Dietary advice in AN

Dietary counselling should only be offered as part of a multi-disciplinary approach.

Encouragement should be given to take an age-appropriate oral multi-vitamin and multi-mineral supplement until the patient’s diet includes enough to meet the dietary reference values.

Include family members or carers (as appropriate) in any dietary education or meal planning for children and young people with AN who are having therapy on their own.

Offer supplementary dietary advice to children and young people with AN and their family or carers (as appropriate) to help them meet their dietary needs for growth and development (particularly during puberty).

Inpatient care

Admission should not be based on a specific weight or BMI threshold but whether the patient can be safely managed in daycare services, e.g. weight loss >1 kg/week or medical need, e.g. bradycardia.

Staff should be aware of the risk of refeeding syndrome and how to manage it (see image…… Chapter 25 ‘Refeeding syndrome’, p. 602).

Guidelines for the Management of Really Sick Patients with Anorexia Nervosa (MARSIPAN) are available for adults24 and those aged <18 years (Junior MARSIPAN).25

Feeding without consent should only be undertaken by competent multi-disciplinary teams and using the framework of the Mental Capacity Act 2005 (see image this chapter).

Post-hospitalization, ongoing care should be planned.

Medication should not be offered as the sole treatment in AN.

Binge eating disorder

ICD-10 descriptor: BED involves regularly eating very large amounts of food over a short period of time, often in an uncontrolled way. Bingeing can occur when not hungry, when alone, or in secret. Eating can continue until feeling uncomfortably full and may be followed by feelings of upset, shame, and guilt. BED includes some of the features of BN but the overall clinical picture does not justify diagnosis, e.g. there may be recurrent bouts of overeating and overuse of purgatives without significant weight change or the typical over-concern about body shape and weight may be absent. Lifetime prevalence is 3.5% for women and 2.0% for men.

Management for adults, children, and young people23

Inform patients that all psychological treatments for BED have limited effect on body weight and that weight loss is not the goal of treatment.

As a first step, encourage the patient to follow an evidence-based BED self-help programme supported by healthcare professionals.

If this not acceptable, contraindicated or ineffective after 4 weeks, offer specifically adapted group CBT-ED.

If this is not available or declined, offer individual CBT-ED.

Medication should not be offered as the sole treatment of BED.

Dietary and eating-related recommendations from NICE guidelines23 include:

advise people to eat regular meals and snacks to avoid feeling hungry;

address emotional triggers for binge eating, using cognitive restructuring, behavioural experiments, and exposure;

monitor weekly binge eating behaviours, dietary intake, and weight, sharing the weight record with the patient;

advise not to diet as likely to trigger binge eating;

aim does not include weight loss, although explain that stopping bingeing is likely to aid weight management in the longer term;

body image issues to be addressed.

Bulimia nervosa

ICD-10 descriptor: BN is characterized by a pattern of overeating (binge eating) followed by purging, which can include self-induced vomiting, taking laxatives, diuretics, diet pills, amphetamines, or excessively exercising (‘exercise debting’). This is to compensate for the excess calories eaten during the binge to prevent weight gain. This disorder shares many psychological features with AN, including over-concern with body shape and weight. Repeated vomiting is likely to give rise to disturbances of electrolytes and physical complications, e.g. stomach acid causing erosion of teeth enamel, oesophageal tears. Excessive laxative misuse can cause constipation. Lifetime prevalence is 1.5% for women and 0.5% for men.


Inform patients that all psychological treatments for BN have limited effect on body weight.

In adults, as a first step, encourage use of a BN-focused self-help CBT programme, supplemented by brief supported sessions with a healthcare professional.

If this not acceptable, contraindicated or ineffective after 4 weeks, offer individual CBT-ED.

In children and young people, offer BN-focused family therapy.

If this not acceptable, contraindicated, or ineffective, offer individual CBT-ED.

Medication should not be offered as the sole treatment of BN.

Treating OSFED

For people with OSFED, consider using the treatments for the eating disorder it most closely resembles.

Physical and mental health co-morbidities

Eating disorder specialists are advised to collaborate with other healthcare teams to support effective treatment of physical or mental health co-morbidities in people with an eating disorder. Outcome measures for both the eating disorder and the physical and mental health co-morbidities should be used to monitor the effectiveness of the treatments for each condition and the potential impact they have on one another. Common mental health co-morbidities seen in eating disorders can include:


Panic and anxiety disorders (including generalized, social anxiety)

Post-traumatic stress disorder

Obsessive compulsive disorder

Obsessive compulsive personality disorder

Emotionally unstable personality disorder

Sleep disorders

Substance abuse or dependence.

Diabetes and eating disorders

For people with an eating disorder and diabetes, the eating disorder and diabetes teams should:

Work in partnership to explain the importance of physical health monitoring to the person.

Agree who will take responsibility for monitoring physical health.

Collaborate on managing mental and physical health co-morbidities.

Use a low threshold for monitoring blood glucose and blood ketones.

Use outcome measurements for each condition to monitor individual treatment efficacy as well as any possible impact they may have on one another.

If misusing insulin, the recommended treatment plan is:

A gradual increase in the amount of dietary carbohydrate (if medically safe), so that insulin can be started at a lower dose.

A gradual increase in insulin dose to avoid a rapid ↓ blood glucose levels, which can ↑ the risk of retinopathy and neuropathy.

Adjusted total glycaemic load and carbohydrate distribution to meet their individual needs and prevent rapid weight gain.

Psychoeducation regarding the physical health problems that result from misuse of diabetes medication.

Diabetes educational intervention if the person has any gaps in their knowledge of diabetes.

When diabetes control is challenging to manage, do not stop insulin altogether, as this puts the person at high risk of diabetic ketoacidosis.

Further reading

BMJ (2017) Eating disorders.


See Box 32.2 for factors influencing eating and drinking in dementia.

Dementia prevalence26

850,000 people in the UK are living with dementia.

7% of people aged >65 years.

42,000 people in the UK aged <65 years.

Prevalence increases with age.

Causes of dementia

Alzheimer’s disease;

Vascular disease;

Lewy body disease;

Huntington’s disease;


Head injury;

Prion disease (e.g. CJD);

Multiple sclerosis;

Wernicke–Korsakoff syndrome;


Box 32.2 Factors influencing eating and drinking in dementia

Poor memory: forgetting to eat or that they have eaten, forgetting to shop or the names of foods to buy

Poor co-ordination: inability to put food onto cutlery, move food into the mouth, peel or unwrap food

Inability to sequence activities needed to prepare meals

Drug side effects: dry mouth, drowsiness, constipation, dysphagia

Poor concentration: easily distracted from meals by noise and other activity

Tremor: spilling drinks, food

Eating slowly: food becomes unappetizing or removed by carer

Poor vision/confusion: food not recognized

Agitation and restlessness: increases energy requirements while reducing opportunities to eat and drink

Hallucinations: reluctance or refusal to eat food that appears to contain foreign bodies

Tooth/mouth problems: pain or discomfort, ill-fitting dentures, tooth decay, altered taste

Choking/swallowing problems: food may be hoarded in the mouth, spat out, taken out or aspirated causing chest infections

‘Sun-downing’: reduced cognitive function in the late afternoon/early evening so meals at this time may not be eaten

Depression: a common additional diagnosis causing poor appetite and reluctance to eat

Professional and lay carers may restrict diets because of additional diagnoses, e.g. diabetes, high cholesterol, diverticulitis, or obesity. This may or may not be appropriate

Improving nutrition

Screening for nutritional risk, e.g. using MUST (see image…… Chapter 25 ‘Malnutrition universal screening tool’, p. 560) or a locally developed nutrition risk screening tool for use within a mental health setting.

Monitoring weight routinely; thinness is common in dementia because food intake is low, not because it is part of the illness.

Where there are concerns regarding weight and nutritional intake, including hydration, monitoring food and fluid intake using daily input and output record charts, which are to be reviewed and escalation procedures followed when indicated.

Maintaining physical activity to help promote appetite and intake.

Tailoring support to what the individual needs: help with shopping, cooking, company at mealtimes, verbal or physical prompts.

Using soft and texture-modified foods only when really necessary.

Asking family carers for advice and information.

Maintaining independence by offering help not interference.

Offering snacks: some older people develop a ‘grazing habit’. Ensuring snacks are nutritious so that total intake is not compromised.

Providing choice by allowing people to select from plates of food that can be eaten immediately.

Avoiding patterned crockery, tablecloths, etc., which may cause visual confusion at mealtimes and distract from the food.

Putting drinks into clear glasses to make them easier to see.

Allowing time for meals: hurried meals may cause agitation and distress.

Limiting noise, distractions, and other activities at mealtimes.

Ensuring adequate lighting so that food can be seen properly.

Talking about food and encouraging eating by chatting about the meal.

Ensuring adequate resources for catering services in institutional settings and in social care packages for people at home.

Ensuring appropriate training for all staff involved in dementia care.

Increasing nutrient intake

Using whole milk or Channel Island milk (approximately 5% fat) rather than skimmed or semi-skimmed milk in cooking and for drinks.

Using sugar (rather than artificial sweeteners) in cooking and drinks.

Making a cooked breakfast available. People with dementia may eat better early in the day.

Including fried foods, cakes, and traditional puddings on menus.

Using alcohol in moderation to stimulate the appetite. This may be offered on its own or added to other drinks before meals.

Making food available at night for those who sleep poorly.

Adding butter, margarine, or grated cheese to mashed potato or other vegetables.

Adding cream, white sauce, butter, or margarine (rather than water or gravy) to food that needs to be pureed.

Offering high energy snacks and drinks between meals (e.g. cake, biscuits, ice cream, instant desserts, trifle, chocolate, sandwiches).

Finger foods

Finger foods (see Table 32.2) may help people who cannot remember how to use cutlery. They may help people maintain independence and dignity by allowing people to feed themselves and the greater interaction with food may increase intake. Finger food menus must be analysed for nutritional adequacy.

Table 32.2 Examples of finger foods

Starchy and cereal Protein-rich Dairy Fruit and vegetables Energy dense
Buttered rolls
Potato cakes
Roast potatoes
Tea cakes
Toast fingers
Chicken nuggets
Fish cakes
Fish fingers
Hard-boiled egg
Cheese cubes
Sliced cheese
Yogurt-covered raisins
Apple slices
Banana pieces
Carrot sticks
Celery sticks
Cherry tomatoes
Orange segments
Ice cream cones
Jam tarts
Slices of cake
Soft foods and modified-texture diets

If a person with dementia has difficulty chewing or swallowing they require assessment by a speech and language therapist to ascertain safe food and fluid textures for the individual as per the International Dysphagia Diet Standardization Initiative image……

Care should be taken to ensure that food provided supplies an adequate energy, protein, and micronutrient intake (see image…… Chapter 23, ‘Dysphagia’, p. 535). Simply liquidizing ordinary food is rarely adequate and oral nutrition supplements should be considered (see Table 25.5, p. 570).

Tube feeding

Enteral nutritional support should be considered for individuals when inadequate intake and/or dysphagia are considered to be transient (see image…… Chapter 25). It is not recommended for those with severe dementia when disinclination to eat is a sign of the gravity of the condition. Decisions to withhold or withdraw nutrition support must be based on ethical and legal principles (see image…… Chapter 35, ‘Palliative care’).27

Mental Capacity Act (MCA) 2005


This Act provides a framework to empower and protect people with limited or no ability to make decisions for themselves. Inability to make a decision may be a result of dementia, mental health issues, learning disabilities, brain injury, a stroke, alcohol or drug misuse, the side effects of medical treatment or other illnesses, or disability. The Act provides guidance and describes duties for people who care for and treat people over the age of 16 years. It defines who can make decisions for them and in which situations, and also describes the process of how this should be done. It facilitates forward planning by allowing people with capacity to anticipate a future time when they are not able to make decisions. The Act covers major decisions such as property and affairs, healthcare, and where they live, as well as day-to-day decisions about what to eat and personal care. It also provides guidance on the use of a Lasting Power of Attorney, Independent Mental Capacity Advocate, and advance decisions concerning life-sustaining treatments. The MCA gives clear guidance regarding:

Helping someone to make their own decisions.

Working out if someone is able to make their own decisions.

Actions to take if someone cannot make decisions.

Deprivation of Liberty Safeguards (DOLS) are a supplement to the MCA. Hospital, residential, and care home staff must understand how people lacking capacity may be deprived of their liberty.

Five key MCA principles

Every adult has the right to make his or her own decisions and must be assumed to have capacity to make them unless it is proved otherwise.

A person must be given all practicable steps to help themselves and these steps must be shown not to work before anyone treats them as not being able to make their own decisions.

Just because an individual makes what might be seen as an unwise decision, they should not be treated as lacking capacity to make that decision.

Anything done or any decision made on behalf of a person who lacks capacity must be done in their best interests.

Anything done for or on behalf of a person who lacks capacity should be the least restrictive of their basic rights and freedoms.

The Act contains a two-stage test of capacity. There are two questions that need to be asked in turn:

1. Is there an impairment of, or disturbance in, the functioning of the person’s mind or brain? This can be temporary or permanent.

If ‘No’, the person is judged to have capacity.

If ‘Yes’ then the second question to follow is …

2. Does this impairment or disturbance mean that the person lacks capacity at this particular time to make a particular decision?

To answer this, a four-stage assessment is used and a person needs to pass each stage to be deemed to have capacity:

1. Do they understand the information relevant to the decision?

2. Are they able to retain this information for long enough to make the decision?

3. Are they able to use or weigh up the pros and cons of the relevant options?

4. Are they able to communicate the decision by any means including non-verbal?

If a person fails the four-stage test, this must be deemed to result from mental impairment for them to be regarded as lacking in capacity.

Care Act 2014

This Act consolidates previous health and social care legislation and guidance with the aim of providing a consistent approach to adult social care. It covers the wellbeing of the person needing support and their carer. This Act states that it is the duty of local authorities to promote physical and mental wellbeing, and it focuses on the provision of person-centred care, preventative support, and integrated services. The act provides a statutory framework for safeguarding adults in England.

Further reading



1Correll, C.U., et al. (2017). Prevalence, incidence and mortality from cardiovascular disease in patients with pooled and specific severe mental illness: a large-scale meta-analysis of 3,211,768 patients and 113,383,368 controls. World Psychiatry 16, 163–180.

2Shaw, K.A., et al. (2009). Tryptophan and 5-hydroxytryptophan for depression. Cochrane Database Syst. Rev. CD003198.

3Appleton, K.M., et al. (2010). Updated systematic review and meta-analysis of the effects of n-3 long-chain polyunsaturated fatty acids on depressed mood. Am. J. Clin. Nutr. 91, 757–70.

4Opie, R.S., et al. (2016). Dietary recommendations for the prevention of depression. Nutr. Neurosci. 20, 161-71.

5Jacka, F.N. et al. (2017). A randomised controlled trial of dietary improvement for adults with major depression (the ‘SMILES’ trial). BMC Med. 15, 23.

6Montgomery, P., Richardson, A.J. (2009). Omega-3 fatty acids for bipolar disorder. Cochrane Database Syst. Rev. CD005169.

7Irving, C., et al. (2010). Polyunsaturated fatty acid supplementation for schizophrenia. Cochrane Database Syst. Rev., CD001257.

8Adamson, J., et al. (2017). Correlates of vitamin D in psychotic disorders: A comprehensive systematic review. Psychiatry Res. 249, 78–85.

9National Institute for Health and Care Excellence (NICE) (2014). Psychosis and schizophrenia in adults: prevention and management. Available at: image……

10National Institute for Health and Care Excellence (NICE) (2013). Psychosis and schizophrenia in children and young people: recognition and management. Available at: image……

11Available at: image……

12Every-Palmer, S., et al. (2016). Clozapine-treated patients have marked gastrointestinal hypomotility, the probable basis of life-threatening gastrointestinal complications: A cross sectional study. EBioMedicine 5, 125-34.

13National Institute for Health and Care Excellence (NICE) (2005). Obsessive-compulsive disorder and body dysmorphic disorder: treatment. Available at: image……

14National Institute for Health and Care Excellence (NICE) (2016). Autism spectrum disorder in adults: diagnosis and management. Available at: image……

15Nye, C., Brice, A. (2009). Combined vitamin B6-magnesium treatment in autism spectrum disorder. Cochrane Database Syst. Rev., CD003497.pub2.

16Isherwood, E., Thomas, K. (2011). Dietary management of autism spectrum disorder: Professional consensus statement. British Dietetic Association, Birmingham.

17Srinivasan, P. (2009). A review of dietary interventions in autism. Ann. Clin. Psychol. 21, 237–47.

18National Institute for Health and Care Excellence (NICE) (2013). Autism spectrum disorder in under 19s: support and management. Available at: image……

19Bent, S., et al. (2009). Omega-3 fatty acids for autistic spectrum disorder: A systematic review. J. Autism Dev. Disord. 39, 1145–54.

20National Institute for Health and Care Excellence (NICE) (2016). Attention deficit hyperactivity disorder: diagnosis and management. Available at: image……

21Gadoth, N. (2008). On fish oil and omega-3 supplementation in children: The role of such supplementation on attention and cognitive dysfunction. Brain Devel. 30, 309-20.

22Beat (2018). Available at: image……

23National Institute for Health and Care Excellence (NICE) (2017). Eating disorders: recognition and treatment. Available at: image……

24Royal Colleges of Psychiatrists, Physicians and Pathologists (2014). MARSIPAN: Management of really sick patients with anorexia nervosa. Available at: image……

25Royal College of Psychiatrists (2012). Junior MARSIPAN: Management of really sick patients under 18 with anorexia nervosa. Available at: image……

26Alzheimer’s Society (2020). Available at: image……

27National Institute for Health and Care Excellence (NICE) (2016). Dementia: supporting people with dementia and their carers in health and social care. Available at: image……