Psychotherapy, in the forms of cognitive-behavioral therapy (CBT), interpersonal therapy, family counseling, nutritional counseling and support groups, is the primary treatment for disordered eating, but patients who binge and purge may find that along with this first-line therapy they're prescribed drug therapy: antidepressants.
Serotoninergic antidepressants, those that regulate the balance of neurotransmitter serotonin in the body, such as the SSRI fluoxetine (Prozac), are effective in reducing the binging-purging cycles of bulimia, a disease that's thought to be partly associated with an imbalance of serotonin.
Binge eaters, patients who binge without purging, consume enormous amounts of calories throughout the day — as much as 5,000 to 15,000 during just one binge — may also benefit from antidepressant drug therapy. SSRIs such as fluoxetine (Prozac), tricyclic antidepressants (TCAs) such as imipramine (Tofranil), and atypical antidepressants including trazadone (Desyrel) are all considered effective in regulating the body's hunger signals in binge-eating disorder (BED).
There are no conclusive studies one way or the other as of mid-2015, but it's considered unlikely that antidepressants are an effective therapy for anorexia nervosa (AN) patients.