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Anorexia nervosa (AN), bulimia nervosa (BN), and
binge eating disorder (BED) are serious conditions that impair both
psychological and physical health. More prevalent in industrialized
nations, these illnesses affect all socioeconomic classes of every
ethnicity in North America (1). Eating disorders (EDs) affect primarily
women, with only 5% to 15% of AN and BN patients and 40% of BED
patients being boys or men (2,3). Three percent of women will be
affected by EDs over their lifetime (4). Collectively, EDs are characterized
by severe disturbances in eating behaviour as well as distress over
body shape and weight.
While the etiology of ED remains elusive, cultural, environmental,
developmental, biological, and genetic factors may all play a role
in their development. In addition to studies of the physiological
and psychosocial aspects of ED, much research has been devoted to
their pharmacologic therapy. This paper reviews the role of medication
in the treatment of AN, BN, and BED.
Anorexia Nervosa
AN is arguably the most lethal of psychiatric illnesses (5). The
key diagnostic features of AN comprise refusal to maintain at least
85% of normal body weight, disturbances in body image, intense fear
of becoming fat, and amenorrhea in postmenarchal girls and women.
DSM-IV suggests 2 categories of AN: the restricting subtype and
the binge or purge subtype. Patients usually appear emaciated, and
the vicious cycle of dieting and weight loss can lead to serious
physiological disruptions, including leukopenia, arrhythmias, prolonged
QT interval, endocrine abnormalities, and osteoporosis. As many
as 15% to 18% of patients will eventually succumb to starvation
or suicide (5).
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Treatment of AN is challenging and usually involves
a multidisciplinary approach. Seriously underweight patients are
best admitted to a hospital or day program where they can receive
psychological counselling with cognitive-behavioural components,
nutritional education, and a diet ensuring 2000 to 4000 calories
daily. Weight gain is essential for AN treatment to be meaningful.
Although pharmacotherapy is a frequent adjunctive intervention,
there is scant evidence for its effectiveness. An impressive pharmacopoeia
has been examined, mainly for the acute phase of AN, with only isolated
and often inconsistent successes. Antipsychotics and lithium were
first studied, to take advantage of their weight-gain side effect.
Antidepressants were investigated because of the noted association
between AN and depressive symptoms. It was hoped that prokinetic
agents could augment weight gain by direct physiological effects,
and zinc piqued curiosity because the clinical features of zinc
deficiency in some ways resemble AN.
Antipsychotics
The antipsychotic chlorpromazine was first studied in the 1960s
(6,7). Although they achieved initial weight gain, patients also
suffered considerable side effects, including grand mal seizures
and increased purging. On long-term study, chlorpromazine yielded
no greater weight gain than that noted in historical control groups.
Other dopamine antagonists were examined in double-blind placebo-controlled
studies (pimozide [8] and sulpiride [9]). While pimozide resulted
in some weight gain over placebo, sulpiride provided no significant
benefit. Neither agent improved patients’ attitudes or behaviours.
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