Motivating Factors That Play a Role in Bulimia Nervosa

Bulimia nervosa (BN) is a serious eating disorder that is characterized by frequent uncontrolled eating binges. These binges are often followed by compensatory behavior, including the following: self-induced vomiting; misuse of laxatives, diuretics, enemas, or other medications to induce purging; fasting; or excessive exercise. If left untreated, BN can lead to many serious health issues: tooth decay; irregular menstruation; bowel damage; constipation; heart and kidney disease; intestinal damage; puffiness, especially in the face and fingers; increased hair growth on the face and body; and mineral imbalances in the body. Similar to drug abuse disorders, food-related thinking and disordered eating behavior can interfere with other occupational and social activities, as well. This study will evaluate whether people with bulimia nervosa will binge eat in a structured laboratory setting and display behavioral patterns similar to those of individuals who are dependent on drugs.

Interested participants will first report to the study site for a screening visit, during which they will be assessed for eligibility using blood tests and an interview. Eligible participants will return to the study site on 3 additional days. Participants will be asked to refrain from eating or drinking between 10 P.M. each night before reporting to the study site and 10 A.M. the next day. Each day, participants will receive breakfast, after which they will not be allowed to eat or drink until the end of the day. Participants will then use a computer program to earn food (a yogurt shake) by tapping on the keyboard. More taps on the keyboard will result in a larger amount of food earned by the end of the day. Once experimentation is complete on Day 1, participants will be instructed to eat as much as they can. On Days 2 and 3, participants will be given a small serving of the yogurt shake prior to beginning the computer task. Following the computer task, they will be instructed to either eat until they are comfortable (without restricting or binging), or eat as much as they can. A private bathroom will be available if needed. All participants, including those who did not meet criteria for participation, will be offered treatment at the study clinic once the study is complete.

Inclusion criteria

Participants with Bulimia Nervosa:

• Meets DSM-IV criteria for bulimia nervosa
• Duration of illness is greater than 1 year
• Self-induces vomiting
• Weighs between 80% and 120% of ideal weight
• Female

Control Group:

• Weighs between 80% and 120% of ideal weight
• Female
• Ages 18-45
• No current or past psychiatric illness
• No history of eating disorder

Exclusion criteria

Participants with Bulimia Nervosa:

• Significant medical illness
• Current Axis I illness other than major depression
• Severe or very severe depression
• At risk for suicide
• Currently taking medication
• History of drug or alcohol abuse within the 6 months prior to study entry
• Pregnant
• Male

Control Group:

• Significant medical illness
• Currently taking medication
• History of drug or alcohol abuse within the 6 months prior to study entry
• Pregnant
• Male
• History of any eating disorder