Other Treatments
Pharmacological
Virtually every type of antidepressant drug has been shown to be
statistically superior to placebos in reducing binge eating and purging
in a number of randomized controlled trials (Wilson et al. 1999).
While different classes of antidepressants seem to be equally effective,
there is evidence that suggests patients who fail to respond to an
initial antidepressant trail may respond to another type of trial
(Mitchell et al., 1989; Walsh, Hadigan, Devlin, Gladis &
Roose, 1991). While the original hypothesis for the treatment
of bulimia with antidepressants was that bulimia nervosa was a variant
of major depression, subsequent studies have disproved this hypothesis
because there is no correlation between level of depression (pre and
post treatment) and the level of symptoms (Craighead & Agras 1991). It is now believed that the efficacy of antidepressants
in bulimia nervosa is primarily the serotonergic
effects of the drugs. Serotonin has influence on eating behaviors
(Craighead & Agras 1991). Studies have
demonstrated that in both humans and animals serotonin is implicated
in carbohydrate consumption and binge behaviors (Craighead &Agras
1991).
Wurtman (1987) has suggested a hypothesis
for a role of serotonin in bulimia and how the raised levels of serotonin
produced by most antidepressants serve to influence eating behaviors.
The theory is that people with bulimia have low endogenous levels
of serotonin in the central nervous system and that their eating habits
are an attempt to elevate the level. The high carbohydrate meals often
consumed in binges are high in tryptophan and low in protein. Tryptophan
(the precursor to serotonin) shares the same transport carrier with
large neutral amino acids derived from proteins. Because of this,
eating foods that are high in carbohydrate content and low in protein
can allow for preferential transport of trytophan
to the brain. Once in the brain, tryptophan can be converted into serotonin and the level
is raised. In this theory, carbohydrate binges serve as a form of
self-medicating the decreased level of serotonin, but if antidepressants
are used to raise the level they should reduce the need to binge (Craighead
& Agras 1991).
However, studies have shown that antidepressant treatments do not
increase the caloric intake of people with bulimia (Angras
& McCann 1987) and this suggests that dietary constraint continues
as a symptom despite reductions in binge and purging behaviors. Consistent
with the serotoneric action of antidepressants,
it makes sense that antidepressants lead to a decrease in eating.
Furthermore, antidepressants may only be a solution with some effectiveness
while they are being taken and not as long term as other approaches.
For these reasons, the APA guidelines call for the use of antidepressants
in the treatment of bulimia only when additional treatments are also
provided.
Other Treatments Subsections:
The American Psychiatric Association Guidelines
Cognitive-Behavioral Therapy
Exposure Plus Response Prevention
Pharmacological Treatments (top
of this page)