Mental Health 529with eating disorders are likely to have prob-
lems getting pregnant. People with anorexia
are likely to suffer from hypotension (low
blood pressure), which could cause cardio-
vascular problems. One study reported pos-
sible long-term effects of anorexia on the
structure of the brain, some of which may
not be reversible (Katzman et al., 1997).Etiology
The etiology of eating disorders is unclear. Eat-
ing disorders often co-occur with other mental
health problems, such as depression, anxiety,
and substance abuse (Hudson et al., 2007).
Researchers have examined genetic links, de-
mographic factors that may predispose one to
eating disorders, social factors, and a variety
of psychological factors, including difficulties
with achievement and lack of control.Biology. It is clear that there is a genetic
component to eating disorders from stud-
ies of twins and from studies of genotypes
(Striegel-Moore & Bulik, 2007). There appears
to be greater heritability of anorexia nervosa
than bulimia (Keel & Klump, 2003). There are
greater cultural differences in bulimia than an-
orexia. Whereas rates of bulimia dramatically
increased over the last half of the 20th century,
rates of anorexia have been stable. Bulimia ap-
pears to be a largely Western phenomenon,
whereas anorexia is not limited to Western
cultures. Given the onset of eating disorders in
adolescence, any biological theory would nec-
essarily have to be an interactive one. Eating
disorders are more common among women
who come from families with a female member
who has an eating disorder. This overlap could
be due to shared genes or shared environment.
Hormones also may play a role in eating
behavior. Prenatal exposure to testosterone
has been linked to a reduced incidence of eat-
ing disturbances, which may partly account
for why females seem to be at greater riskthan males. The relation of eating disorders to
testosterone was examined in a study of same-
sex and other-sex twins, reasoning that fe-
male other-sex twins have greater exposure to
testosterone than female same-sex twins
(Culbert et al., 2008). Results supported the
theory. The highest rate of eating disorders
was found in female same-sex twins, followed
by female other-sex twins, followed by male
other-sex twins, and then male same-sex twins.Demographics. Females are more likely
than males to have eating disorders and dis-
turbed eating behavior, but the sex differ-
ence is smaller for binge eating disorder and
disturbed eating behavior (Striegel-Moore &
Bulik, 2007). Overall, the effect sizes are
smaller than one would think, so it is impor-
tant to realize that men also can suffer from
eating disturbances (Striegel-Moore et al.,
2009). Historically, higher socioeconomic
status was viewed as a risk factor for eating
disorders, and minority persons were less vul-
nerable to eating disorders than Caucasians.
Today, it is no longer the case that eating dis-
orders are limited to upper class Caucasian
girls (Crow, 2010; Harrison & Hefner, 2008).
Females and males with eating disor-
ders have a similar age of onset and similar
symptoms (Woodside et al., 2001). One dif-
ference is that homosexuality is a risk fac-
tor for eating disorders among men but not
women. Eating disorders are more common
among gay men than heterosexual men but
not among lesbians compared to heterosex-
ual women (Peplau et al., 2009), perhaps be-
cause of a greater preference for thinness and
higher body dissatisfaction among gay men
(Boroughs & Thompson, 2002).Female Gender Role. Eating disorders
have been linked to features of the female gen-
der role. First, the female gender role places a
high value on physical attractiveness. Second,M13_HELG0185_04_SE_C13.indd 529 6/21/11 12:55 PM