Chapter 10 – Eating Disorders
• Eating disorder not otherwise specified (EDNOS): The most common
eating disorder diagnosis characterize by heterogeneous symptoms and
associated features that do not fit the symptoms of other eating disorders.
This diagnosis is applied to between approximately 40 and 70% of
• There is also newly proposed variations known as purging disorder, which
is a form of bulimia that involves self-induced vomiting or laxative use at
least once a week for a minimum of six months.
• Once clear feature of purging disorder is high impulsivity.
• Co-twins of patients diagnosed with anorexia nervosa, for example, are
themselves more likely than average to have bulimia nervosa.
• Anorexia nervosa (AN). Anorexia refers to loss of appetite, and nervosa
indicates that this is for emotional reasons. The term is something of a
misnomer because most patients with anorexia nervosa actually do not
lose their appetite or interest in food. Most patients with the disorder
become preoccupied with food; they may read cookbooks constantly and
prepare gourmet meals for their families.
• The person must refuse to maintain a normal body weight
• The person has an intense fear of gaining weight, and the fear is not
reduced by weight loss.
• Patients with AN have a distorted sense of their body shape. The
tendency to link self-esteem and self-evaluation with thinness is known as
“overevaluation of appearance.
• In females, the extreme emaciation causes amenorrhea, the loss of the
menstrual period. Of the four existing diagnostic criteria, amenorrhea
seems least important.
Physical Changes in Anorexia Nervosa
• Blood pressure often falls, heart rate slows, kidney and gastrointestinal
problems develop, bone mass declines, the skins dries out, nails become
brittle, hormone levels change, and mild anemia may occur. Some
patients lose hair from the scalp, and they may develop laguna, a fine, soft
hair, on their bodies. Levels of electrolytes such as potassium and sodium
• Deficits in white-matter volumes in the brain are restored upon-recovery
from anorexia nervosa, but deficits in grey-matter volumes appear
• Anorexia is associated with a 25 year reduction in life expectancy. Bulimia Nervosa
• Bulimia nervousa (BN). Bulimia is from a Greek word meaning “ox
hunger”. This disorder involves episodes of rapid consumptions of a large
amount of food, followed by compensatory behaviours, such as vomiting,
fasting, or excessive exercise, to prevent weight gain. The DSM defines a
binge as eating an excessive amount of food within less tan two hours.
• They report that they lose control during a binge, even to the point of
experiencing something skin to a dissociative state, perhaps losing
awareness of what they are doing or feeling that it is not really they who
• As with anorexia, two subtypes of bulimia nervosa are distinguished: a
purging type and a non-purging type in which the compensatory
behaviours are fasting or excessive exercise.
Binge Eating Disorder
• DSM-IV-TR includes binge eating disorder (BED) as a diagnosis in need
of further study rather than a formal diagnosis but BED will be included in
• Binge eating disorder appears to be more prevalent than either AN or BN.
• As possible role for genetics is suggested by the fact that both anorexia
nervosa and bulimia nervosa run in families. First-degree relatives of
young women with anorexia nervosa are about four times more likely than
average to have the disorder themselves.
Eating Disorders and The Brain
• The hypothalamus is a key brain centre in regulating hunger and eating.
Research on animals with lesions to the lateral hypothalamus indicates
that they lose weight and have no appetite.
• A dysfunctional hypothalamus dos not seem a highly likely factor in
anorexia nervosa however.
• Endogenous optoids are substances produced by the body that reduce
pain sensations, enhance mood, and suppress appetite, at least among
those wih low body weight. Opioids are released during starvation and
have been viewed as playing a role in both anorexia and bulimia.
Starvation among patients with anorexia may increase the levels of
endogenous opioids, resulting in a positively reinforcing euphoric state
that has been characterized as powerfully reinforcing. Furthermore, the
excessive exercise seen among some patients with eating disorders
would increase opioids and thus be reinforcing. • Bulimia is mediated by low levels of endogenous opioids, which are
thought to promot