To the Editor: The editorial by O"Brien, et al. argues that classification of substance use disorders should use the term “addiction” instead of “dependence,” which involves normal physiological adaptations. They argue that confusing “dependence” with “addiction” prevents pain patients from getting needed “additional pain medication” (p. 764). A problem with this argument is the implicit underlying assumption that sustained opioid pain medication is continuously effective for chronic pain, and more opioid medication is more effective. The evidence, however, is to the contrary. Chronic opioid intake results in multiple, overlapping physiological adaptations that counteract the analgesic effects of opioids and even enhance pain sensitivity (1, 2). A recent review of the effects of sustained opioid intake concluded that opioids given chronically, at least in high doses, are neither safe nor effective (3). Differentiating addiction from dependence has been promulgated as a way to determine which chronic pain patients may safely be prescribed opioids. This belief corresponds with the marked increase in prescription of strong opioids in recent years and a simultaneous increase in morbidity and mortality from prescription drug dependence (4, 5). Psychiatrists are receiving more and more referrals of chronic pain patients dependent on opioids. In our experience, whether or not they have been behaviorally compliant, they usually do better when detoxified and treated with nonopioid analgesics and psychiatric support (6, 7). In contrast, increasing the opioid dose will provide no more than temporary benefit. We are aware that many patients can function satisfactorily while maintained on steady doses of opioids, such as methadone maintenance patients. When chronic pain patients are managed in this fashion, it may not be pain that is being treated, but rather this may be a form of office-based opioid maintenance. Whatever the terminology that is used for substance use disorders, the assumption that if a patient is not an addict they can be treated freely with opioids will not diminish suffering and will often increase it (8).