Further defining and conceptualizing opioid misuse in chronic pain.

The recent review by Vowles et al. 5 on the rates of opioid misuse, abuse, and addiction in chronic pain is a sorely needed step in the right direction toward better defining and understanding the prevalence of opioid misuse, abuse, and addiction among individuals with chronic pain. The authors are to be applauded for both synthesizing and advocating for literature using explicit definitions of opioid misuse (ie, not taken exactly as prescribed), abuse (ie, intentional use for nonmedical purposes such as euphoria), and addiction (ie, continued use despite harm or with impaired control, compulsion, or craving). Unfortunately, these distinct terms have too often been conflated in past research and surveillance, which may result in inaccurate data collection, interpretation, and counterproductive treatment approaches. 4 Although the authors provide a compelling synthesis of the literature using these terms, still a more precise definition of opioid " misuse " is needed. In their review of 38 studies, the authors found misuse to be the most common form of problematic opioid use (at a weighted average rate of 21%-29%). However, as noted in the discussion, the actions constituting misuse in the studies were extremely broad, many of which may not be appropriately classified as problematic opioid misuse. For instance, " underuse, " " overuse, " and " erratic or disorganized use " of opioids all fell under the definition of problematic misuse, whereas we would argue that these classifications should remain distinct from one another. Furthermore, " use of opioids in conjunction with alcohol or illegal substances (eg, marijuana) " was classified as opioid misuse, presumably even if an individual continued to take their opioid medication exactly as prescribed. Such a classification is problematic in that it: (1) seems to suggest that any opioid-prescribed individual who uses alcohol or other substances is automatically considered to be misusing opioids, when in reality the misuse may be more related to the other substance being used rather than the opioid; (2) does not coincide with the growing body of research exploring adjunct analgesic treatments to opioid therapy for chronic pain, such as the potentially beneficial effect of cannabinoids alongside opioid therapy 1–3 ; and (3) perpetuates the dangerous notion that remains prevalent in the literature and in clinical care, which assumes that substance use and pain are mutually exclusive conditions and that individuals who use illicit substances in addition to opioid therapy may be immediately suspected to …