WASHINGTON – Proposed DSM-5 criteria for sleep-wake disorders include dropping the DSM-IV’s "primary insomnia" diagnosis in favor of "insomnia disorder," and decreasing use of the term "not otherwise specified."
The changes reflect a move away from the need to make causal attribution between coexisting disorders and also the overall DSM-5 shift toward more data-driven diagnostic criteria, said Dr. Charles F. Reynolds III, professor of geriatric psychiatry, neurology, and neuroscience at the University of Pittsburgh.
"Sleep-wake disorders" is one of 13 diagnostic categories that are undergoing revision from the DSM-IV to the DSM-5, slated for publication in May 2013. Dr. Reynolds is chair of the seven-member Sleep-Wake Disorders Work Group that devised the proposed diagnostic criteria, which – along with the rest of the DSM-5 proposed criteria – will be open for a third and final round of comments from visitors beginning this spring. As before, comments will be systematically reviewed by each of the work groups for consideration of additional changes.
The proposed criteria are meant to be used by nonpsychiatrists and psychiatrists who are not sleep specialists. "We are trying very much to propose a classification and a set of criteria that are friendly [and] clinically useful for the general mental health clinician and to the general medical clinician, because very few users will have specific expertise in sleep disorders medicine," said Dr. Reynolds, also professor of behavioral and community health sciences at the university’s graduate school of public health. "We don’t think such expertise will be necessary. At the same time, our hope is that with these criteria and with the accompanying text, that the general user will feel more confident about when to consult a sleep disorder specialist."
Sleep disorders per se are frequently accompanied by depression, anxiety, and other cognitive mental status changes that must be addressed in treatment planning and management. The differential diagnosis of complaints such as insomnia and daytime sleepiness necessitates consideration of coexisting medical and neurologic conditions, and requires a multidimensional approach. "Coexisting clinical conditions are the rule, not the exception," he noted.
Proposed Terminology Changes
The proposed DSM-5 criteria replace terminology that causally attributes coexisting conditions with a simple listing of the comorbidities. This was done to underscore that the patient has a sleep disorder warranting independent clinical attention in addition to the psychiatric and medical disorders also present. In addition to the switch from "primary insomnia" to "insomnia disorder," the diagnoses of "sleep disorder related to another mental disorder" and "sleep disorder related to a general medical condition" also are proposed to be dropped in favor of "insomnia disorder" or "hypersomnia disorder," along with specification of clinically comorbid medical and psychiatric conditions.
This approach acknowledges bidirectional or interactive effects between sleep disorders and coexisting psychiatric conditions such as depression. It also has implications for treatment. For example, a patient who has persistent insomnia even after adequate treatment for depression might be at increased risk for relapse of the depression, or for worsening of cognitive impairment, and might therefore require independent evaluation of the sleep problem, Dr. Reynolds noted.
In an effort to improve diagnostic precision, use of "insomnia not otherwise specified" is proposed to be reduced by elevating both "REM sleep behavior disorder" and "restless leg syndrome" to full-fledged diagnoses. This recommendation is based on a large amount of epidemiologic, pathophysiologic, genetic, and controlled clinical trial data, he said.
Another proposal is to further subtype circadian rhythm sleep disorders into delayed sleep phase type; advanced sleep phase type; and irregular sleep–wake type, –free-running type, –jet lag type, and –shift work type. Yet another proposal would subtype breathing-related sleep disorder into obstructive vs. central in order to inform treatment planning.
Other Proposed Modifications
Other major proposed changes include distinguishing narcolepsy/hypocretin deficiency from other forms of hypersomnia disorder, which illustrates the increased emphasis on using biomarkers in the DSM-5 where doing so would be scientifically appropriate and clinically practical, he noted.
An example of the effort to move away from expert opinion to evidence-based diagnostic criteria is the proposed "primary hypersomnia/narcolepsy without cataplexy" category. In the DSM-IV, the criteria are "unexplained hypersomnia (excessive sleep) or/and hypersomnolence (sleepiness in spite of sufficient nocturnal sleep), for at least 3 months, occurring 3 or more times per week," with "hypersomnia" defined by a prolonged nocturnal sleep episode or daily sleep amounts (more than 9 hours/day).
In the proposed DSM-5 revision, the definition of hypersomnia includes thresholds: Excessive sleepiness that occurs three or more times per week, for 3 or more months, despite a main sleep lasting 7 hours or longer. Evidence supporting this comes from a recent cross-sectional telephone survey of 15,929 individuals who were representative of the adult general population of 15 U.S. states. A total of 27.8% reported "excessive sleepiness," and 15.6% had recurrent periods of irrepressible need to sleep or to nap within the same day (13.2%); recurrent naps within the same day (1.9%); a nonrestorative (unrefreshing), prolonged main sleep episode of 9 hours or more per day (0.7%); and/or confusional arousals (sleep drunkenness) (4.4%).