Neither obesity nor simple overeating will be included in the DSM-5, the forthcoming revision to the Diagnostic and Statistical Manual of Mental Diseases, but binge eating is on track to become a formal psychiatric diagnosis, it was reported here.

The addition of binge eating is one of several changes within the eating disorders category in the DSM, according to B. Timothy Walsh, MD, of Columbia University in New York City, head of the DSM-5 work group in this clinical area.

But, said Walsh in a report here at the American Psychiatric Association’s (APA) annual meeting, he and his colleagues did not believe there was enough hard evidence to support creating a psychiatric diagnosis for obesity or overeating.

“We don’t have the data to merit anything beyond binge eating,” he said. “We have to follow the field, not lead it.”

But he held out the possibility that some kind of overeating syndrome, distinct from binge eating, might be added in the future. “I would not dismiss the theoretical basis” for considering overeating a psychiatric condition, he said.

Darrel Regier, MD, MPH, the APA’s research director, commented that a number of studies have suggested that people who eat excessively have biological similarities, in terms of neural firing patterns, to those with substance addictions.

Trimming EDNOS

Walsh told attendees that the eating disorders category had cried out for an overhaul. The current edition of the DSM lists just three types for adults: anorexia, bulimia, and eating disorders not otherwise specified (EDNOS).

Studies reviewed by the work group suggested that up to 45% of all patients treated for eating disorders receive a diagnosis of EDNOS, an indication that the current classifications are inadequate.

Three additional diagnoses were initially proposed to take patients out of EDNOS, Walsh said. In addition to binge eating disorder, these were purging disorder and night eating syndrome.

Purging disorder would have covered patients with bulimia symptoms but without any abnormal eating habits. Night eating syndrome was intended for patients who get up in the night to eat an extra meal, but who wouldn’t qualify as binge eaters.

In the end, according to Walsh, the work group decided that these would be premature. They may be included in an appendix to the DSM-5, a sort of holding tank for symptom bundles that need more study before acceptance as officially recognized disorders.

Indeed, binge eating is in the appendix of the current DSM.

Defining Binge Eating

Criteria for diagnosing binge eating disorder will be tested in field trials set to begin this summer.

The primary definition is that patients eat amounts at one sitting that are “definitely larger than most people would eat in a similar period of time under similar circumstances,” and the patient must also perceive a lack of control over the amount eaten.

Binges must occur at least once a week for three months, and patients must express “marked distress” over them.

In addition, patients must have at least three of the following associated behaviors or symptoms:

  * Eating much more rapidly than normal
  * Eating until feeling uncomfortably full
  * Eating large amounts of food when not feeling physically hungry
  * Eating alone because of being embarrassed by how much one is eating
  * Feeling disgusted with oneself, depressed, or very guilty after overeating

Walsh said there was ample evidence in the literature that binge eating is distinct from bulimia and is clearly not just an extreme of normal behavior.

He acknowledged that distinguishing a binge from a large meal is somewhat subjective. “It is not a sharp line in the sand,” he said.

On the other hand, he said, patients who meet the proposed criteria show definite abnormalities in laboratory testing - i.e., they eat more at a sitting than people who don’t meet the criteria.

Anorexia and Bulimia

Also in the offing are some changes to the diagnostic criteria for anorexia and bulimia.

The current definition had been criticized in part because it included an example of “85% of recommended body weight” as an indicator that a person was too thin. Walsh said the work group agreed that this figure, though not a hard and fast criterion for diagnosis, was arbitrarily restrictive.

In the revision, the first criterion has been reworded to say “restriction of energy intake [leading to] markedly low weight.”

Other criteria have undergone minor wording changes as well, and amenorrhea has been dropped entirely from the list of symptoms that may be associated with anorexia.

For bulimia, a diagnosis will be easier than before because of a change in the required frequency of binge-purge episodes.

Whereas the current DSM specifies that episodes must occur twice a week for the previous three months, the new criteria allow a diagnosis when the frequency is once a week.

The new binge eating category and the anorexia and bulimia revisions should greatly cut down on EDNOS diagnoses, Walsh said.

Analysis of 247 calls to an eating disorder clinic indicated that only 15% would receive an EDNOS diagnosis under the new criteria, compared with 39% using the existing system, he said.

Childhood Eating Disorders

Walsh said the infant and childhood eating disorders category would undergo little change.

Pica and rumination disorder criteria will remain largely intact.

Children now classed as having “feeding disorder of infancy and early childhood” - reflecting a lack of interest in food for no medically apparent reason - may receive a new diagnosis, avoidant-restrictive food intake disorder.

But he said the scientific evidence on the relevant symptoms is scant. “We know they exist but there is almost no literature,” he said, adding that the main basis for creating a diagnosis is simply that parents come to child psychiatrists seeking help.

——
By John Gever, Senior Editor, MedPage Today
Published: May 29, 2010
Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco.