BNF Recommendations for the Treatment of Wernicke’s Encephalopathy: Lost in Translation?

In response to our suggestion to define substance use disorders via ‘heavy use over time’, theoretical and conceptual issues, measurement problems and implications for stigma and clinical practice were raised. With respect to theoretical and conceptual issues, no other criterion has been shown, which would improve the definition. Moreover, heavy use over time is shown to be highly correlated with number of criteria in current DSM-5. Measurement of heavy use over time is simple and while there will be some underestimation or misrepresentation of actual levels in clinical practice, this is not different from the status quo and measurement of current criteria. As regards to stigma, research has shown that a truly dimensional concept can help reduce stigma. In conclusion, ‘heavy use over time’ as a tangible common denominator should be seriously considered as definition for substance use disorder. We thank their authors for the four commentaries (Bradley and Rubinsky, 2013; Heather, 2013; Rice, 2013; Saunders, 2013) on our suggestion to replace the current definitions of substance dependence, use disorders, abuse and harmful use by heavy use over time (Rehm et al., 2013a). Here, we attempt to answer the points raised. We see four major threads of discussion: (a) Theoretical considerations that the essence of addictions is different than currently defined by DSM and ICD, and that the reformulation of heavy use over time does not capture this point (Heather, 2013; Saunders, 2013). This has a corollary that definitions other than heavy use over time or heavy use over time itself can better explain phenomena currently associated with addictive behaviour (Bradley and Rubinsky, 2013; Saunders, 2013). (b) Problems with assessing heavy consumption over time (Bradley and Rubinsky, 2013; Saunders, 2013). (c) The usefulness of various concepts in reducing stigma and in clinical practice (Bradley and Rubinsky, 2013; Rice, 2013). (d) Using heavy use as one of several criteria for defining substance use disorders (Bradley and Rubinsky, 2013). Starting with the theoretical considerations, we made our arguments that almost all of what is currently conceptualized under the heading of addiction or use disorders is a consequence of heavy use over time (Rehm et al., 2013a). Obviously, we used the current definitions of DSM IV, DSM 5 and ICD 10 as starting points. Both Rice and Saunders note that these definitions have strayed quite far from the single dimension of Saunders’ ‘internal drive’—the dimension that has been at the heart of the addiction concept as it was invented in post-Enlightenment European cultures (Levine, 1978). As Rice notes, DSM-5’s adoption of the term ‘substance use disorder’ further cements this separation. The addiction concept essentially puts forward an explanation rather than a description: an explanation in terms of a mysterious force driving behaviour. In the wake of the St. Louis revolution in psychiatric nosology (Room, 1998), psychiatric classification in the USA, and increasingly elsewhere, has favoured description over the kind of psychodynamic hypothesis represented by the classic addiction concept. An explanation in terms of a mysterious force that cannot be fully modelled in animal or neurobiological research can actually be argued to be obstructive of scientific progress. However, we agree that the situation ‘that some people continue to use heavily despite knowing that their heavy use is causing the negative consequences’ (Heather, 2013) is worth continued investigation (see also (European Monitoring Centre for Drugs and Drug Addiction, 2013), where this concept is discussed in more detail), and in fact one of the authors has emphasized the importance of investigating automatically triggered or implicit processes in substance use disorders (Wiers and Stacy, 2006), exactly to understand these psychological processes. However, while these processes may be associated with the phenomenon of continued heavy use they are not necessary to characterize it. When we scrutinize the additional criteria proposed by the commentators, we do not see a necessity to include other criteria. For instance, all the correlations with other phenomena that Saunders (2013) cites to demonstrate what he believes is the core of addiction and its consequences are also true for heavy use over time. To give an example, the amount of heavy use over time is highly correlated with the number of criteria fulfilled in current definitions; so, it is no surprise that the correlations with outcomes are similar. To illustrate this, we have undertaken a cross-tabulation of alcohol dependence (last year) with level of use in the US National Epidemiologic Survey on Alcohol and Related Conditions, separated by treatment status (see Table 1). The more symptoms, the higher the consumption, with higher consumption in people with lifetime treatment. Similarly, in a Catalonian cohort of people treated for alcohol dependence, level of use, sex and age ‘explained’ 94% of the variance of DSM III R symptoms (for a description of the cohort (Gual et al., 1999)). Significant associations were also found in the 2012 German Epidemiological Surveys of Substance Abuse, not only for alcohol but also for tobacco, cannabis and cocaine (data not shown; for a description see (Kraus et al., 2013)). To conclude: all relevant effects used to demonstrate the evidence for the usefulness of current criteria or for the number of criteria as a measure of severity would be replicated by levels of heavy use, as the two measures are highly correlated. And as demonstrated in our original paper, the heavy use over time concept better explained the relationships with negative health outcomes (Rehm et al., 2013a). Thus, as heavy use over time is the simplest concept, we should just use this, unless there are clear indications that other concepts better explain relevant phenomena that heavy use over time cannot do. As for the understanding of an ‘internal drive’ (Saunders, 2013), we believe that it is enough that heavy use over time leads to changes in the brain, which Table 1. Average alcohol intake in grams per day by number of DSM-IV criteria fulfilled for alcohol dependence (last year), by whether treated in lifetime: from data of the US National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) Gender Number of criteria of DSM-IV for alcohol dependence