In the face of scant literature on the subject, the investigators aim to more clearly identify effective treatments for adolescent bulimia nervosa (BN) through a treatment study comparing two current treatments (Cognitive Behavioral Therapy for Adolescents, CBT-A and Family Based Therapy for Bulimia Nervosa, FBT-BN) for the disorder in comparison with a non-specific therapy, Supportive Psychotherapy for Adolescent Bulimia (SPT). Additionally, the investigators hope to provide clinicians with information on treatment efficacy, variables that might influence outcome, and processes that may affect treatment efficacy that will guide them in their efforts to treat adolescent BN.

BN is a serious disorder that is characterized by extreme concerns about body weight and shape, dieting, and the disinhibited eating behaviors of binging and purging. There are no published randomized clinical trials of psychotherapy treatment for Bulimia Nervosa in adolescents although it often onsets in this age group. There is evidence that some treatments are effective, but none has been empirically tested. Because Bulimia Nervosa is a serious medical and psychiatric illness it is important to learn efficacious ways to treat this disorder, especially in its early stages. Treatments used in this study are the best known treatments for adults with Bulimia Nervosa. The investigators hope to learn which of two previously studied treatments might be superior to the other, in an effort to guide clinicians in treatment choices. Successfully treating the disorder early on (even in those adolescents with partial BN, characterized by binge eating and purging at least one time per week over a 6 month period) may reduce the number of cases requiring treatment during adulthood, leading to possible reduction in severity of associated psychopathology and lower costs, as well as enable individuals to lead more productive lives.

Given the neglect of adolescent BN in the research literature and the need for information to guide the clinical treatment of this disorder, this study's primary aim is to compare the efficacy of CBT-A to FBT-BN in decreasing binge eating and purging episodes in adolescents with BN and partial BN (defined as binge eating and purging at least one time per week for the past six months).

Participation in this study will last 1 and a half years and will consist of 6 months of treatment and a follow-up session at 6 and 12 months post-treatment. All participants will first undergo baseline assessments, which include interviews and questionnaires about psychological history and BN symptoms, and an Eating Disorder Examination (EDE) interview. All treatment assignments consist of 18 sessions of therapy over the course of 6 months.

Inclusion Criteria:

1. Participants will be adolescents living with at least one of their parents and between the ages of 12 and 18 years of age with a DSM IV diagnosis of BN or partial BN (binge eating and purging at least one time per week over a six month period).
2. Males meeting inclusion criteria will also be entered into the study. They must have age-adjusted BMI greater than 17.5, or ideal body weight (IBW) > 85%.
3. Family, for the purposes of this study, includes members of the subject's household, including at least one parent or adult guardian. Single parent families, divorced families, step-parents, and other types of families will be allowed to enter the study.

Exclusion Criteria:

1. psychotic illness or other mental illness requiring hospitalization; bipolar I disorder, depression with active suicidal thoughts and behavior;

2. associated physical illness that necessitates hospitalization;

3. current dependence on drugs or alcohol;

4. current diagnosis of anorexia nervosa or weight less that 85% IBW;

5. physical conditions (e.g. diabetes mellitus, pregnancy) known to influence eating or weight;

6. currently taking medication for co-morbid conditions for less than 2-months;

7. currently taking medications that may induce weight loss, e.g., appetite suppressants such as sibutramine, phentermine, and xenical, unless the participant is willing to withdraw from such medications;

8. currently taking medications for symptoms of BN and unwilling to discontinue these prior to initiating treatment in the study

9. previous CBT or FBT treatment for BN

10. married subjects

11. emancipated minors

12. family members will be excluded from engaging in treatment for the following reasons:

    • Current or history of sexual or physical abuse of the patient by family members. Perpetrators of the abuse will be excluded from treatment. Should sexual or physical abuse by a family member occur during the course of treatment, perpetrators will be excluded from ongoing treatment.
    • Substance dependence, psychosis, or severe medical illness that would limit full participation in therapy, or that might put the family member at risk for worsening of their condition during treatment. The decision whether or not to allow these individuals to continue to participate in treatment will be made by the therapist in consultation with the treatment supervisor.