Binge eating disorder has been added in DSM-5 as a diagnosis for individuals who experience persistent, recurrent episodes of overeating marked by loss of control and significant clinical distress.
That’s the major change of which clinicians will be aware in the chapter on feeding and eating disorders in DSM-5. Other changes include the elimination of the requirement for amenorrhea in criteria for anorexia nervosa, a change to the frequency threshold in criteria for bulimia, and inclusion in the chapter of several disorders previously classified as eating disorders of infancy or childhood. Criteria for a newly named avoidant/restrictive food intake disorder (previously included as a disorder of infancy and childhood) have also been expanded.
Meanwhile, the most important overall change to criteria for sleep-wake disorders is a move away from causal attributions between sleep disorders and other medical or mental disorders, underscoring that sleep disorders may exist independently of the other disorders with which they frequently co-occur and may need to be the focus of clinical attention and treatment in their own right.
This information appears in “Feeding and Eating Disorders” and “Sleep-Wake Disorders,” respectively, the ninth and 11th chapters in Section II of DSM-5, to be published in May. (The 10th chapter, on elimination disorders, contains no changes from DSM-IV.)
The multiaxial system of previous editions has been eliminated, and chapters are now arranged according to a “lifespan,” or developmental, approach—disorders affecting children appearing first and those more common in older individuals appearing later. Development of criteria and organization of the text in the new manual are marked by several overarching themes: incorporation of a developmental approach to psychiatric disorders, recognition of the influence of culture and gender on how psychiatric illness presents in individual patients, a move toward the use of dimensional measures to rate severity and disaggregate symptoms that tend to occur across multiple disorders, harmonization of the text with ICD, and integration of genetic and neurobiological findings by grouping clusters of disorders that share genetic or neurobiological substrates.
In an interview with Psychiatric News, Timothy Walsh, M.D., chair of the Work Group on Feeding and Eating Disorders, said an enormous amount of research in the last several decades—more than 1,000 published papers—justifies the inclusion of binge eating disorder. He said its inclusion will help to significantly decrease the use of “eating disorder—not otherwise specified.”
Walsh said the criteria—which describe persistent episodes of overeating at least once a week, marked by loss of control and clinically significant distress—are sufficiently restrictive to differentiate the diagnosis from the kind of periodic overeating that is normative in contemporary society.
“We have good data to indicate that if the criteria are rigorously applied by people familiar with the syndrome, only a relatively small number of people will meet the criteria,” Walsh told Psychiatric News. “Individuals with the disorder exhibit a loss of control and are markedly distressed by the behavior, to the extent that they will sometimes avoid eating with other people.
“The lifetime prevalence of the disorder we believe is less than 5 percent, and we have good data that individuals who meet the criteria have a significantly higher frequency of anxiety and depression.”
Avoidant/restrictive food intake disorder is a category intended to capture individuals—typically, but not exclusively, children—who have extreme, idiosyncratic preferences and requirements for food that lead to psychological or nutritional problems. Previously listed in DSM-IV as eating disorder of infancy or childhood, the diagnosis was rarely used, Walsh said.
“What our group recommended was to retitle the disorder and expand it to include a broader range of behaviors designed to capture people—often but not exclusively children—who develop significant problems with food intake and run into nutritional problems,” Walsh explained. “An example is a child who develops a pattern of only eating foods of a certain texture or color—say, food that is white. Lots of children have these kinds of idiosyncrasies, but in rare cases the behaviors are extreme and cause nutritional problems.”
Pica and rumination disorder, previously listed as disorders of infancy and childhood, are now distinct categories in the DSM-5 chapter on feeding disorders, indicating that the diagnosis can be made for individuals of any age.
Core criteria for anorexia nervosa are conceptually unchanged, but the requirement in DSM-IV for amenorrhea has been eliminated. And the frequency threshold for binge eating and inappropriate compensatory behavior in the criteria for bulimia nervosa has been lowered from twice a week to once a week.
A fundamental theoretical and organizational change to criteria for sleep-wake disorders is the removal of causal associations between sleep disorders and the medical or mental disorders with which they frequently co-occur.
“The key point is that sleep-wake disorders don’t occur in isolation but typically with other disorders, such as depression, osteoarthritis, or congestive heart failure,” work group chair Charles Reynolds, M.D., said in an interview. “In DSM-IV, we might have diagnosed someone as having insomnia due to depression or heart failure. But in DSM-5, we are asking clinicians to specify the sleep disorder and to list co-occurring disorders.
“The sleep disorder may exist independently but interact with the co-occurring disorder and thus warrant clinical attention in its own right to have an optimal outcome.”
Reynolds noted, for instance, that if insomnia that occurs along with depression is not treated, depression is likely to recur. “We think that rather than making causal attributions, the clinician should recognize that there is a two-way street—a bidirectional association—between sleep and other disorders, and both require clinical attention. Often the co-occuring disorders are mutually exacerbating.”
Reynolds told Psychiatric News that a 2005 National Institutes of Health consensus conference of sleep experts argued for a new focus on comorbidity and coexisting conditions, as opposed to the DSM-IV approach of causal attribution. “That has greatly influenced the direction in DSM-5,” he said.
DSM-5 also distinguishes narcolepsy, which is now known to be associated with hypocretin deficiency, from other forms of hypersomnolence.
Two new diagnoses—REM sleep behavior disorder and restless legs syndrome—have been added, which should significantly reduce the use of sleep disorder–not otherwise specified.
Finally, the criteria for insomnia include a frequency threshold of three nights per week and duration of at least three months. The text also includes dimensional measures of severity.
“This speaks to the concept of measurement-based care, a pervasive theme that has informed the entire DSM-5,” Reynolds told Psychiatric News. “Clinicians will see in the accompanying text a listing of useful dimensional measures of sleep impairment to help them understand how troublesome the symptoms are and to measure improvement as patients go through treatment. The dimensional measures will also help researchers correlate measures of severity with underlying brain dysfunction.” ■