Participants at four treatment sites will be screened for diagnosis, health, and presence of other conditions through assessments in standardized questionnaires, clinical interviews, and a blood test. Participants who pass the screening will be randomly assigned to one of two treatment sequences. In the first sequence, participants will be given twenty 50-minute sessions of individual CBT treatment over 18 weeks, focusing on altering eating behaviors. If participants do not have an adequate initial response to treatment by session six, they will be offered a trial of fluoxetine in addition to their continued CBT treatment. If they do not meet response criteria at the end of the 18 weeks of CBT treatment, they will again be given the option of taking or continuing to take fluoxetine until the termination of the study. The second sequence will begin with a specially designed self-help program aimed at teaching the same skills that will be taught in CBT sessions. Participants will have nine 30-minute checkup sessions with a therapist over 18 weeks. Participants who do not respond adequately to the treatment after 10 weeks will be given the option of taking fluoxetine. Participants without sufficient recovery at the end of 18 weeks will be given the option of undergoing the first treatment sequence.