Bulimia nervosa, commonly known as bulimia, is an eating disorder. It is generally considered a psychological condition in which the subject engages in recurrent binge eating followed by an intentional purging. This purging is done in order to compensate for the excessive intake of the food and to prevent weight gain. Purging typically takes the form of vomiting; inappropriate use of laxatives, enemas, diuretics or other medication; and excessive physical exercise. The word bulimia comes from the Latin (būlīmia) from the Greek βουλῑμια (boulīmia), ravenous hunger, compounded from βους (bous), ox + λῑμος (līmos), hunger.
Causes
Bulimia is often less about food, and more to do with deep psychological issues and profound feelings of lack of control. Binge/purge episodes can be severe, sometimes involving rapid and out of control feeding that can stop when the sufferers "are interrupted by another person" or when their stomach hurts from over-extension. This cycle may be repeated several times a week or, in serious cases, several times a day. Sufferers can often "use the destructive eating pattern to gain control over their lives".

In one study, high testosterone and low estrogen levels were correlated with a diagnosis of bulimia, and normalizing these levels with oral contraceptives reduced cravings for fat and sugar.
Environmental factors
The disorder is more prevalent in Caucasian groups, but is becoming a rising problem in the African American and Hispanic communities. Males are just as prone to having eating disorders as women. There are higher rates of eating disorders in groups involved in activities that put an emphasis on thinness and body type (such as gymnastics, dance and cheerleading, figure skating, and other sports and activities in which a slender body is believed to be most appealing).
Definition
An eating disorder, common especially among young women of normal or nearly normal weight, that is characterized by episodic binge eating and followed by feelings of guilt, depression, and self-condemnation. It is often associated with measures taken to prevent weight gain, such as self-induced vomiting, the use of laxatives, dieting, or fasting.
Patterns of bulimic cycles
The frequency of bulimic cycles will vary from person to person; the severely ill might binge and purge several times a day. Some people may vomit automatically after they have eaten any food. Others will eat socially but may be bulimic in private. Some people do not regard their illness as a problem, while others despise and fear the vicious and uncontrollable cycle they are in [9]. Bulimics claim to use this as a stress reliever or a way to cope with "life" circumstances. Others are just so frighteneed of gaining weight that they have to revert to what they call "purging". They may appear to be underweight, normal weight or even overweight. Every bulimic is completely different in "how much" they purge. Some binge, some don't. Oftentimes when the urge "hits", they will go to great lengths to purge. It's almost like an uncontrollable urge or force is making them do it. Medical evidence shows that the chemicals released when purging make a person feel "high". This can also lead to extreme dehydration and electrolyte imbalances.

Subtypes of bulimia
The specific subtypes of bulimia are distinguished by the way the bulimic relieves themselves of the binge.

Purging type
The purging type involves self-induced vomiting, laxatives, diuretics, tapeworms, enemas, or ipecac, as a means of rapidly extricating the contents from their body. This type is generally more found, and can use one or more of the above methods.
Non-Purging Type
This type of bulimia is rarely found (occurring in only approximately 6%-8% of cases), as it is a less effective means of ridding the body of such a large number of calories. This type of bulimia involves engaging in excessive exercise or fasting following a binge in order to counteract the large amount of calories previously ingested. This is frequently observed in purging-type bulimics as well, however this method is, by definition, not their primary form of weight control following a binge.

Consequences of bulimia nervosa
Bulimia can result in following health problems:

Malnutrition
Dehydration
Electrolyte imbalance (Can lead to Cardiac Arrest, which can also result in brain damage by stroke)
Hyponatremia
Damaging of the voice
Vitamin and mineral deficiencies
Teeth erosion and cavities, gum disease
Sialadenosis (salivary gland swelling)
Potential for gastric rupture during periods of binging
Esophageal reflux
Irritation, inflammation, and possible rupture of the esophagus
Laxative dependence
Peptic ulcers and pancreatitis
Emetic toxicity due to ipecac abuse
Swelling of the face and cheeks, especially apparent in the lower eyelids due to the high pressure of blood in the face during vomiting.
Callused or bruised fingers
Dry or brittle skin, hair, and nails, or hair loss
Lanugo
Edema
Muscle atrophy
Decreased/increased bowel activity
Digestive problems that may be triggered, including Celiac, Crohn's Disease
Low blood pressure, hypotension
Orthostatic hypotension
High blood pressure, hypertension
Iron deficiency
Anemia
Hormonal imbalances
Hyperactivity
Depression
Insomnia
Amenorrhea
Infertility
High risk pregnancy, miscarriage, still-born babies
Diabetes
Elevated blood sugar or hyperglycemia
Ketoacidosis
Osteoporosis
Arthritis
Weakness and fatigue
Chronic Fatigue Syndrome
Cancer of the throat or voice box
Liver failure
Kidney infection and failure
Heart failure, heart arrhythmia, angina
Seizure
Paralysis
Potential death caused by heart attack or heart failure; lung collapse; internal bleeding, stroke, kidney failure, liver failure; pancreatitis, gastric rupture, perforated ulcer, depression and suicide.

Diagnosis
As mentioned earlier, all six of the criteria listed in the DSM are required for a classic diagnosis of bulimia nervosa. However, these symptoms are often difficult to spot, especially since, unlike anorexia nervosa, in order to be classified as bulimic the person must be of normal or higher weight. Likewise, the person is less likely to drop a significant amount of weight on a continual basis as does the anorexic, making the physical symptoms less noticeable, despite the fact that internal bodily functions are suffering. Because this disorder carries a great deal of shame, the bulimic will desperately try to hide their symptoms from family and friends. This disorder is more likely to span over a lifetime unnoticed, causing a great deal of isolation and stress for the suffering individual. Despite the frequent lack of obvious physical symptoms, bulimia nervosa has proven to be fatal, as malnutrition takes a serious toll on every organ in your body. If any of the symptoms above are noticed one should consult with a doctor or psychologist for further assistance.

Related psychological disorders
It is not uncommon that a patient with bulimia nervosa will also have some anxiety or mood disorder as well. Most commonly associated with bulimia is the incidence of anxiety, one study noted this in 75% of bulimic patients. Also prominent in bulimic patients are mood disorders, most commonly depression as well as substance abuse issues. However recent researchers suggest that depression is a consequence of the eating disorder itself, rather than the other way around. They are also more likely to attempt suicide, and engage in impulsive behaviors.

Differences between anorexia nervosa and bulimia nervosa
The main criteria differences involve weight, as an anorexic must technically be classified as underweight.