When seriously underweight, many individuals with anorexia nervosa have depressive signs and symptoms such as depressed mood, social withdrawal, irritability, insomnia, and diminished interest in sex. Because these features are also observed in individuals without anorexia nervosa who are significantly undernourished, many of the depressive features may be secondary to the physiological sequelae of semi-starvation, although they may also be sufficiently severe to warrant an additional diagnosis of major depressive disorder.
Obsessive-compulsive features, both related and unrelated to food, are often prominent.
Most individuals with anorexia nervosa are preoccupied with thoughts of food. Some col- lect recipes or hoard food. Observations of behaviors associated with other forms of star- vation suggest that obsessions ancl compulsions related to food may be exacerbated by undemutrition. When individuals with anorexia nervosa exhibit obsessions and compul- sions that are not related to food, body shape, or weight, an additional diagnosis of obses- sive-compulsive disorder (OCD) may be warranted.
Other features sometimes associated with anorexia nervosa include concerns about eating in public, feelings of ineffectiveness, a strong desire to control one’s environment, inflexible thinking, limited social spontaneity, and overly restrained emotional ex- pression. Compared with individuals with anorexia nervosa, restricting type, those with binge-eating/purging type have higher rates of impulsivity and are more likely to abuse alcohol and other drugs.
A subgroup of individuals with anorexia nervosa show excessive levels of physical ac- tivity. Increases in physical activity often precede onset of the disorder, and over the course of the disorder increased activity accelerates weight loss. During treatment, exces- sive activity may be difficult to control, thereby jeopardizing weight recovery.
Individuals with anorexia nervosa may misuse medications, such as by manipulating dosage, in order to achieve weight loss or avoid weight gain. Individuals with diabetes mellitus may omit or reduce insulin doses in order to minimize carbohydrate metabolism.
The 12-month prevalence of anorexia nervosa among young females is approximately 0.4%. Less is known about prevalence among males, but anorexia nervosa is far less com— mon in males than in females, with clinical populations generally reﬂecting approximately a 10:1 female-to-male ratio.
Anorexia nervosa commonly begins during adolescence or young adulthood. It rarely be- gins before puberty or after age 40, but cases of both early and late onset have been de- scribed. The onset of this disorder is often associated with a stressful life event, such as leaving home for college. The course and outcome of anorexia nervosa are highly variable.
Younger individuals may manifest atypical features, including denying "fear of fat.” Older individuals more likely have a longer duration of illness, and their clinical presentation may include more signs and symptoms of long-standing disorder. Clinicians should not exclude anorexia nervosa from the differential diagnosis solely on the basis of older age.
Many individuals have a period of changed eating behavior prior to full criteria for the disorder being met. Some individuals with anorexia nervosa recover fully after a single episode, with some exhibiting a ﬂuctuating pattern of weight gain followed by relapse, and others experiencing a chronic course over many years. Hospitalization may be re— quired to restore weight and to address medical complications. Most individuals with an- orexia nervosa experience remission within 5 years of presentation. Among individuals admitted to hospitals, overall remission rates may be lower. The crude mortality rate (CMR) for anorexia nervosa is approximately 5% per decade. Death most commonly results from medical complications associated with the disorder itself or from suicide.
Temperamental. Individuals who develop anxiety disorders or display obsessional traits in childhood are at increased risk of developing anorexia nervosa.