OPIOID-RELATED DISORDERS CLASSIFICATION AND DIAGNOSIS
What's in a Name? Opiate versus Opioid
It may seem trivial to distinguish between an opiate and an opioid, the terms being frequently used interchangeably and incorrectly by the medical community. However, there are significant differences between the classes that have some practical impact (results of urine drug testing, for instance, can be more easily interpreted using knowledge of the differences). Put simply, although all opiates are also opioids, not all opioids are opiates. An opioid is any natural or synthetic chemical that has opium-like effects similar to those of morphine. All opioids bind to opioid receptors in the central nervous system (CNS). Opiates, on the other hand, are a specific type of opioid derived directly from the opium poppy and include opium, codeine, morphine, and thebaine. Ingestion of an opiate will produce an opiate-positive result using immunoassay urine drug screens. Other non opiate opioids have been either modified from an opiate (semisynthetic) or created de novo (synthetic). Semisynthetic opioids demonstrate variable sensitivity in toxicology testing, whereas fully synthetic opioids, including fentanyl and methadone, will not be positive with an opiate screen and require additional tests. The term "narcotic"—derived from the Greek "narkotikon" meaning "to numb"—is a generally outdated and nonspecific term referring to illicit drugs, often opioids, that induce sleep, numbness, or stupor.
The criteria for opioid use disorders have changed under the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM)-5, which defines Opioid Use Disorder under the broader category of Substance-Related and Addictive Disorders. Individuals with opioid use disorders may be using a number of different substances ranging from prescription opioids to illicit substances such as heroin. As described in Chapter 48, there are special considerations when diagnosing an opioid use disorder in light of the expected neuroadaptation (i.e., tolerance and withdrawal) that develops after prolonged prescription opioid therapy. Opioids are commonly used medically to suppress cough or to relieve pain. Therefore, when opioids are taken solely under appropriate medical supervision, DSM-5 excludes tolerance and withdrawal from the criterion list, requiring at least 2 of 9 (rather than of 11) criteria to support a diagnosis of an opioid use disorder. Without being able to rely on the signals of tolerance or withdrawal for diagnosis, clinicians must concentrate on the following three symptom clusters for diagnostic clarity: (1) loss of control (i.e., the substance is taken in larger amounts or over a longer period than was intended, or there are unsuccessful efforts to control use), (2) salience to the behavioral repertoire (i.e., a great deal of time is spent using or recovering from use, important activities are given up because of use, or use is continued despite great physical, psychological, occupational, or interpersonal consequence or risk), and (3) craving (strong desire to use opioid). Severity is determined by symptom count with the presence of 2–3 symptoms required ...