But neither CBT nor IPT alone has proven useful for weight loss. Thus far, however, adding concurrent pharmacologic agents or other therapeutic modalities to CBT has yielded inconsistent results.
In a recent randomized, placebo-controlled study by Dr. Grilo and his associates, CBT was significantly superior to fluoxetine, and the addition of fluoxetine to CBT did not produce any further benefit than did the addition of placebo to CBT in either binge eating behavior or weight loss among 108 patients (Biol. Psychiatry 2005;57:301–9).
In an older randomized study that compared the addition of fluoxetine or placebo to behavior modification in 45 obese subjects–22 with binge eating problems and 23 without–weight loss was significantly greater among those taking fluoxetine, but the results did not differ between the binge eaters and the nonbinge eaters (Am. J. Psychiatry 1990;147:876–81).
In another of Dr. Grilo's recent studies, 50 obese BED patients on guided self-help CBT were randomized to receive 12-week concurrent treatment with either 120 mg orlistat three times a day or placebo. In the intent-to-treat analysis, 36% of the orlistat group achieved weight loss of 5% or greater, compared with just 8% of the placebo group. At 3 months' follow-up, those rates were 32% and 8%, with comparable rates of improvement in both eating disorder psychopathology and psychological distress (Biol. Psychiatry 2005;57:1193–201).
Studies of sibutramine (Meridia), an antiobesity medication (Arch. Gen. Psychiatry 2003;60:1109–16), and the antiepileptic topiramate (Topamax) have also shown significant reductions in binge eating and weight loss compared with placebo, although the latter had a high discontinuation rate (J. Clin. Psychiatry 2004;65:1463–9).
Finally, recent data have reinforced the benefits of guided self-help CBT over guided self-help behavioral weight loss (BWL) programs in reducing the frequency of binge eating (Behav. Res. Ther. 2005;43:1509–25) and of individual CBT in reducing binge eating behavior, compared with those who did not receive CBT among 116 overweight/obese BED patients who all received BWL treatment over 20 weeks (Obes. Res. 2005;13:1077–88).
“It's very clear that CBT is the best available treatment for obese persons who binge eat,” Dr. Grilo said. “It's superior to medications and behavioral weight loss in producing remission in binging and improving psychological profile. But, it does not appear to be useful for weight loss. Adding orlistat might be one way to go, but we need more data.”
But Dr. Walsh pointed out, there are no data looking at the efficacy of commercial weight loss programs such as Weight Watchers in people who meet the BED criteria. “Do they really need CBT, or are standard weight loss programs just as good? That's a very important question.”
Dr. Grilo and Dr. Walsh think the answers might come from two particular ongoing studies, both funded by the National Institutes of Health. One, being conducted at Washington University in St. Louis, is looking at the long-term impact of 24 weeks' treatment with the three major psychological approaches (CBT, interpersonal therapy, and behavioral weight loss) in BED. The other trial, from Dr. Grilo's group, is comparing CBT and BWL (“dieting”) separately and also in sequence to see whether CBT followed by BWL is effective in reducing both binge eating and weight for up to 1 year post treatment.
Data from both studies are expected in mid-2007.
DSM-IV Research Criteria for BED
A. Recurrent episodes of binge eating. An episode of binge eating is characterized by both of the following:
(1) eating, in a discrete period of time (e.g., within any 2-hour period), an amount of food that is definitely larger than most people would eat in a similar period of time under similar circumstances
(2) a sense of lack of control over eating during the episode (e.g., a feeling that one cannot stop eating or control what or how much one is eating)
B. The binge eating episodes are associated with three (or more) of the following:
(1) eating much more rapidly than normal
(2) eating until feeling uncomfortably full
(3) eating large amounts of food when not feeling physically hungry
(4) eating alone because of being embarrassed by how much one is eating
(5) feeling disgusted with oneself, depressed, or very guilty after overeating
C. Marked distress regarding binge eating is present.
D. The binge eating occurs, on average, at least 2 days a week for 6 months.
Note: The method of determining frequency differs from that used for bulimia nervosa; future research should address whether the preferred method of setting a frequency threshold is counting the number of days on which binges occur or counting the number of episodes of binge eating.