New research suggests that involving parents in the treatment of adolescents with bulimia nervosa is more effective than treating the patient individually.

Researchers found that family based therapy was clinically superior to cognitive based or individual therapy with 49 percent of teens receiving family based therapy abstaining from binging and purging versus 32 percent for cognitive based therapy.

"Parents need to be actively involved in the treatment of kids and teens with eating disorders," researcher Daniel Le Grange of the University of California-San Francisco said in a statement. "This study shows definitively that parental engagement is imperative for a successful outcome of adolescents with bulimia nervosa. It goes counter to the training that physicians receive in psychiatry, which teaches that parents are to blame for bulimia, and therefore should be omitted from treatment."

Bulimia is characterized by recurrent episodes of uncontrolled overeating, called binge episodes. These binge episodes are followed by compensatory behaviors aimed at preventing weight gain, such as self-induced vomiting, laxative or diuretic abuse, fasting, or intense exercising. Between one and three percent of teens suffer from the condition each year in the United States, and most develop the disorder during their adolescence.

For the study, researchers compared two treatments, cognitive behavioral therapy and family based therapy. The former focuses on the individual patient, stressing skills training that helps patients gain a thorough understanding of themselves and the irrational thoughts that are causing them to binge and purge. By recognizing and confronting these irrational thoughts, they can change their behavior and healing can occur. Family based therapy works with parents to understand the severity of the disorder and learn how to best support their children on a daily basis to keep them medically safe, and support healthy habits.

They randomized 130 adolescents age 12 to 18 with bulimia nervosa to either receive cognitive behavioral therapy or family based therapy. Treatments included 18 outpatient sessions over six months, with follow-up at six and 12 months.

They found that participants in family based therapy achieved higher abstinence rates from binging and purging than the patients in individual cognitive based therapy. At the end of initial treatment, 39 percent of family based therapy patients were abstaining from binging and purging versus 20 percent of cognitive based therapy patients, and at the six-month follow-up 44 percent of family based patients were not bingeing and purging versus 25 percent of patients who received cognitive based therapy.

"These findings are quite clear," Le Grange said. "Family based therapy is the treatment of choice for adolescents with bulimia nervosa, because it works quicker and faster and maintains its impact over time. "

The findings are detailed in the Journal of the American Academy of Child and Adolescent Psychiatry.