Most people will be familiar with the terms anorexia nervosa and bulimia nervosa, both of which are ten times more common in females and can have a serious effect on the individual's physical health. However, disordered eating due to mental health extends beyond those conditions explicitly classified as eating disorders. This entry looks at the different causes of self-imposed starvation and overeating.

Anorexia and Bulimia

These conditions are covered in the following entries:

• Anorexia Nervosa
• Bulimia Nervosa

A key feature in both these disorders is a pathological dread of being overweight, thus causing the sufferer to take abnormal measures to avoid weight gain at all costs. In anorexia, a very low target weight is set and is achieved through malnutrition and excessive exercise. This leads to a raft of problems that can prove fatal if the disorder remains untreated. In bulimia, there is instead a paradoxical craving of food that leads to binge eating, which is offset by purging and weight loss tactics similar to those found in anorexics. Note that some anorexics may binge eat and purge through vomiting – the difference is that anorexics intend to lose weight, whereas bulimics aim to counteract the weight gain from overeating.

Binge Eating Disorder

Binge eating disorder is a relatively new diagnosis that involves binges similar to those seen in bulimia nervosa but without the compensatory purging, dieting or exercise. To qualify as a binge, the amount eaten over a fixed period (eg three hours) must be definitely in excess of the societal norm. Also, there must be a feeling of lack of control over the eating behaviour, such that the individual feels they cannot stop eating or control the type or amount of food eaten. Other characteristics must also be present (three of the following):

• Increased speed of eating
• Eating until uncomfortably full
• Eating large quantities of food when not hungry
• Eating alone due to embarrassment regarding the amount eaten
• Feelings of disgust, depression or extreme guilt after binges

In order to make a diagnosis of binge eating disorder, the binges must have occurred at least twice a week for six months, and there must be marked distress caused by the binge eating.

Other Disorders Affecting Eating

Depression: As well as a reduced appetite, depression can in fact lead to comfort eating and a resultant increase in weight. Severe depression can produce a large decrease in appetite that may lead to a loss of several kilograms of body weight, and individuals with symptoms of self-neglect may fail to eat and drink at all. It is worth noting that, whereas depressed individuals eat less due to a loss of interest in food, anorexics tend to still be interested in food but will refuse to eat. However, it is not uncommon for anorexics to become depressed as a result of their starvation.

Mania: Individuals experiencing an episode of mania may neglect to eat due to excessive activity, and may also become dehydrated and exhausted through their actions.

Obsessive compulsive disorder: individuals who are pre-occupied with compulsions may forget to eat properly and end up losing weight as a result. Also, obsessions relating to poisoning of food can obviously interfere with an individual's diet. Note that a diagnosed anorexic should not be diagnosed with OCD unless they have obsessions relating to things other than food and body shape.

Psychoses: psychotic individuals may have auditory hallucinations or delusions that prevent them from accepting food. Self-neglect is also an issue in patients with schizophrenia and can lead to starvation. On the other hand, some antipsychotics are associated with weight gain, though this may be managed to some extent by appropriate dieting and exercise.

Dementia: individuals with memory problems and difficulty performing common tasks due to dementia can easily fail to eat properly if not properly supported.

Substance misuse: alcohol and drug abuse can lead to malnutrition due to problems with normal functioning and due to financial issues and homelessness.

Treatment

The treatment of eating problems differs according to the cause, and so will not be covered here. However, two interesting points are worth mentioning:

• Emergency electroconvulsive therapy is used in severely depressed patients who have stopped eating and drinking and whose health is therefore at risk.

• While the Mental Health Act (1983) does not allow treatment of physical disease to be given against a sectioned patient's will, it does allow for the feeding of emaciated anorexics, as weight gain has been shown to improve the symptoms of anorexia.