This article first appeared in the ANZAED 2011/2012 Summer Newsletter. It has been reprinted courtesy of the authors and ANZAED.
When DSM V is launched in early 2013 it will be almost two decades since DSM IV was introduced in 1994. In the two decades preceding DSM IV, Bulimia Nervosa had not yet been described, so what great developments in classification have the last two decades spawned? In essence DSM V represents a gradual evolution of the thinking presented in DSM IV rather than the seismic shift some were advocating”
So what’s new in DSM V?
Binge Eating Disorder
With DSM V now seeing Binge Eating Disorder graduating from the Appendix to the main body of the manual, this will hopefully drag some of the amorphous “NOS” hordes along with it. And surely it is a good thing to clearly recognise that people who have out-of-control binges with associated disgust, embarrassment &/or guilt and distress about this problem have a mental illness and should be treated as such – hopefully more helpfully than via obesity or weight control measures alone.
Some small changes in diagnostic criteria should have some significant impact on clinical diagnosis.
Amenorrhea is gone as an inclusion category. This category was unhelpful in relation to males, pre-pubescent or menopausal females and women menstruating solely through being on the contraceptive pill. Amenorrhoea is simply one of many markers of malnutrition and in many ways was superfluous given the weight related criteria incorporated in the diagnosis of AN.
“Refusal to maintain weight” is replaced in DSM V by “Restriction of energy intake relative to requirements”. The term refusal was thought to imply a deliberateness to an individual’s action, requiring the clinician to have a clear understanding of a persons motivation to make a diagnosis of AN. As any clinician knows this is not only difficult but has the capacity to imply blame. The ability to make this judgement on the basis of both behaviour and corroborative history represents a significant move forward and matches the way clinicians using the diagnostic criteria for their patients
DSM IV refers to non-“maintenance of body weight at or above a minimally normal weight for age and height”, It gives examples of “weight loss.. or failure to make expected weight gain…leading to body weight less than 85% of expected”.
DSM V simply states “weight that is less than minimally normal, or, for children and adolescents, less than that minimally expected”, omitting the example/guideline of 85% bodyweight. In contrast, ICD10 is more specific, requiring body weight in AN to be of at least 15% below the normal or expected weight for age and height.
This loosening of weight criteria in DSM V has a number of possible ramifications. It does leave more responsibility on the clinician to make the judgement about how critical the low weight is, which may be a problem for less experienced clinicians, greater flexibility does allow criteria such as weight history, body type, physical compromise to be more seriously considered as decision points.
This is particularly helpful in children where amount and rate of weight loss predict risk of severe medical complications rather than absolute weight. Similarly it is psychological pathology (abnormal body image and fear of weight gain) which are generally better predictors of severity than weight at presentation. It may have been useful for DSM V to include stage of illness as a factor, to discriminate between conditions of initial onset, recovery, relapse and chronicity.
Neveretheless, it is likely that the lack of strict weight criteria will increase the number of people diagnosed with AN in lieu of EDNOS.
Frequency of Binging: Binge eating and inappropriate compensatory behaviours need only occur at least once a week (DSM V) rather than twice a week (DSM IV) over a 3 month period. This adjustment is based on research evidence that people who binge once a week have the same level of, eating disorder pathology, the same level of functional impairment, similar rates of psychiatric comorbidity and the same response to treatment as people who binge/purge more often. This criterion will probably increase the numbers of people diagnosed as BN.
The subtyping in DSM IV (Purging vs non-purging) is gone. This should not be of great consequence, as the non-purging subtype is rarely seen and indeed has received relatively little attention in the literature. If anything the non-purging subtype more closely resembles Binge Eating Disorder…
This category, renamed Feeding and Eating Conditions Not Elsewhere Classified, (FECNEC?), has a number of informal subcategories described for possible future inclusion. These include: Atypical Anorexia Nervosa (higher weight), Subthreshold Bulimia Nervosa (low frequency or limited duration), Subthreshold Binge Eating Disorder (low frequency or limited duration), Purging Disorder (in the absence of binge eating), Night Eating Syndrome, and the even more residual category Other Feeding or Eating Condition Not Elsewhere Classified.
Many expect and indeed hope that the prevalence of EDNOS/FECNEC will reduce due to the changed criteria in AN, the loosening of binge criteria in BN and the inclusion of BED. However in contrast, others such as Chris Fairburn often talk about the large group of “transdiagnostic” individuals who inevitably will vacillate between symptom patterns, and for whom a more specific diagnosis such as AN or BN is neither possible nor helpful.
So what other implications are there of these changes:
- With changes to diagnostic criteria potentially altering the inclusion and exclusion criteria in research studies, the smallish changes to AN and BN should not make a huge differences while the two year roll-in will allow researchers time to prepare.
- The increased definitions of the old EDNOS category should allow for greater tailoring of treatments, and facilitate the development of approaches for conditions such as purging disorders and night eating syndrome.
For more information visit the American Psychiatric Association website.
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