This study will evaluate the effectiveness of the drug baclofen in reducing binge eating and associated food cravings in people with bulimia nervosa or binge eating disorder.

Bulimia nervosa (BN) and binge eating disorder (BED) are serious eating disorders that are characterized by frequent uncontrolled eating binges. Binge eating is associated with both psychological and physical health problems, such as depression, obesity, stomach problems, and heart problems. Treatment options for binge eating, however, are limited. Baclofen, a drug that enhances the GABA-B neurotransmitter's ability to inhibit neuronal activity in the brain, is commonly used as a muscle relaxant. It has also been shown, however, to have positive effects on binge eating when used in animals and on substance abuse when used in humans. This study will evaluate the effectiveness of baclofen in reducing binge eating and associated food cravings in people with BN or BED.

People interested in participating in this study will first report to the study site for two initial visits, which will involve blood tests and interviews regarding medical history. If eligible, participants will take part in this 13-week open-label study. Participants will take baclofen 3 times a day, before meals, for 10 weeks. Baclofen dosages will be low to begin, followed by a gradual increase over a 2-week period. Upon reaching the maximum tolerated dose of baclofen, participants will continue at this dosage level until Week 11, at which time the dose will be gradually decreased. If any serious side effects occur, baclofen dosage will be decreased to the previous tolerated dosage level. Participants will also keep a daily record of any episodes of binge eating. Study visits will be held biweekly. At each visit, participants will be interviewed by a psychiatrist about their mental health history and eating patterns, and will fill out questionnaires about their eating habits, emotional states, and any side effects. Phone interviews will be conducted during the weeks in between study visits.

Inclusion Criteria:

For people with BN:

• Meets DSM-IV criteria for BN
• Disease duration is more than 1 year
• Self-induces vomiting
• Weighs between 80 and 120% of ideal weight
• Binge eats on at least 6 days during the 2-week run-in period

For obese people with BED:

• Meets DSM-IV criteria for BED
• Obese (body mass index [BMI] is greater than 30 kg/m²)
• Binge eats on at least 6 days during the 2-week run-in period

Exclusion Criteria:

For all participants:

• Significant medical illness
• Current or lifetime history of schizophrenia, bipolar disorder, or other psychotic disorder as defined by DSM-IV-TR
• Moderate to severe depression as defined by a score greater than 18 on the Hamilton Depression Scales
• Current DSM-IV-TR diagnosis of organic mental disorder, factitious disorder, or malingering
• History of a personality disorder (e.g., schizotypal, borderline, or antisocial) that might interfere with assessment or compliance with the study procedures
• At risk for suicide
• Currently taking medication other than birth control pills or over-the-counter medication
• History of drug or alcohol abuse within 3 months prior to study entry
• Pregnant, planning to become pregnant, or breast feeding
• Known intolerance to baclofen, or related muscle relaxants
• Orthostatic hypotension

Additional exclusion criteria for people with BN:

• Underweight (BMI less than 18 kg/m²)