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Letters to the Editor The journal publishes both invited and unsolicited letters.
METHODOLOGICAL AND PRACTICAL LIMITATIONS TO VISUALLY DETERMINING INTOXICATION In response to Graham et al.’s [1] recent contribution entitled ‘Reducing intoxication among bar patrons: some lessons from prevention of drinking and driving’, we would like to highlight a sample of the salient methodological and practical pitfalls associated with developing a ‘valid and reliable measure of intoxication based on observable behavior’ (p. 697). For a more detailed discussion and contextualization of these limitations, we recommend that interested readers consult Brick & Erickson [2]. Tolerance Simply stated, functional tolerance occurs when the brain adapts, and begins to compensate for, the influence of alcohol on both bodily function and behavior [3]. That said, development of functional tolerance occurs at different rates for the various psychomotor functions, cognitive tasks and bodily functions that are impacted by alcohol [4–6]. Chronic alcohol users can reach blood alcohol concentration (BAC) levels that may incapacitate or kill others (i.e. BACs ≥ 400–500 mg/dl), while at the same time masking the accompanying visual signs of intoxication that less experienced drinkers may exhibit [7–14]. Thus, visually determining intoxication is dependent not only upon (i) the individual characteristics of the patron, but also (ii) the task being observed and (iii) the tolerance level of the person performing the tasks. To further complicate visual identification of intoxication, it is noteworthy that tolerance can be both (i) dependent upon the setting in which the behaviour occurs and (ii) learned. Tolerance to the effects of alcohol can be accelerated if alcohol is consumed within the same environmental context, or accompanied by the same external stimuli [3,15–18]. Additionally, if tasks are practised while drinking, it is possible that tolerance can be learned or behaviorally augmented [3]. In other words, ‘development of ethanol tolerance is sensitive to the same training procedures which facilitate drug-free learning of a task’ ([19], p. 329). Tolerance associated with a specific context/environment or a certain task, however, is not transferrable to novel stimuli or unpractised conditions [20,21]. Sensitivity and specificity Depending upon the outcome of interest, there are varying levels of acceptable sensitivity and specificity. © 2013 Society for the Study of Addiction
Unfortunately, the current evidence-base suggests that a visual test for intoxication would lack high rates of either. For instance, after watching a target enter a room, sit in a chair, engage in a standard interview and subsequently exit, four groups of social drinkers were asked to rate four different targets on level of intoxication [i.e. sober, moderately intoxicated (50 mg/dl), or very intoxicated/legally drunk (100 mg/dl)]. Only four of the 16 categorical assessments were accurate, none of which included the legally intoxicated targets [22]. Physicians’ and emergency nurses’ ability to detect acute alcohol intoxication among trauma patients has also exhibited poor sensitivity (23% of patients with a BAC > 100 mg/dl were not identified) and specificity rates (patients were more likely to be falsely classified as intoxicated if young, male, disheveled, uninsured or having a low income) [23]. While physical manifestations (i.e. staggering gait, glazed eyes, slurred speech) have demonstrated some utility in determining intoxication, these manifestations—individually and in combination—were examined at excessive intoxication levels (i.e. BAC of 0.15% and higher) [24]. That said, even at blood alcohol concentrations above 100 mg/dl, only small proportions (21%) of drivers (n = 1115) were identified correctly as intoxicated [25]. Thus, among average drinkers, ‘signs of visible intoxication are not readily observed at BACs that currently define intoxicated driving (80 md/dl)’ ([2], p. 1498). When considering chronic drinkers specifically, ‘at BACs of less than the 150 mg/dl range, most (i.e. >50%) will not appear visibly intoxicated’ ([2], p. 1498). Previous attempts to establish an observational instrument It is noteworthy that an observational instrument designed to assess alcohol intoxication visually, the 11-item Alcohol Symptom Checklist (ASC), has already been developed [26]. Developers of the ASC contend that initial psychometric testing confirms ‘the scale’s reliability, its interrater consistency, and its predictive validity’ ([26], p. 459). Subsequent evaluation and testing, however, documented exceedingly low correlations between the ASC ratings and a plasma alcohol concentration [27]. More recent testing of the ASC with patients presenting at an emergency department confirmed the questionable utility of observational instruments, concluding that ‘outward physical signs of intoxication do not correlate well with BACs as measured by alcohol testing’ ([28], p. 4). Addiction, 109, 851–854
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852
Letters to the Editor
Overall, there is limited evidence that current premiselevel interventions will reduce intoxication [29]. Thus, as Graham et al. [1] assert, rethinking our approach to reducing patron intoxication levels is both necessary and recommended. Unfortunately, the ability to detect alcohol intoxication visually, even among trained professionals such as police officers, physicians and alcohol counselors, has been erratic at best (2,22,23,30–32). Inability to reliably assess intoxication visually is due to the fact that ‘no behavioral or physical sign has emerged that is consistently related to a specific level of BAC without large variation among individuals’ ([33], p. 134). Given this constellation of factors, building future initiatives on the unreliable shifting sands of subjective determinations of visual intoxication does nothing to further future research efforts and may, in fact, serve as a hindrance. Declaration of interests None. ADAM E. BARRY 1 & MAURICE E. DENNIS 2
Department of Health Education and Behavior, University of Florida, Gainesville, FL 32611, USA1 and Texas A&M Traffic Institute, College Station, TX, USA2. E-mail: [email protected] References 1. Graham K., Miller P., Chikritzhs T., Bellis M. A., Clapp J. D., Hughes K. et al. Reducing intoxication among bar patrons: some lessons from prevention of drinking and driving. Addiction 2014; 109: 693–8. 2. Brick J., Erickson C. K. Intoxication is not always visible: an unrecognized prevention challenge. Alcohol Clin Exp Res 2009; 33: 1489–507. 3. National Institutes on Alcohol Abuse and Alcoholism. Alcohol and tolerance. Alcohol Alert 1995; 28: PH 356. 4. Pohorecky L. A., Brick J., Carpenter J. A. Assessment of the development of tolerance to ethanol using multiple measures. Alcohol Clin Exp Res 1986; 10: 616–22. 5. Tabakoff B., Kiianmaa K. Does tolerance develop to the activating, as well as the depressant, effects of ethanol? Pharmacol Biochem Behav 1982; 17: 1073–6. 6. Vogel-Sprott M. D. Acute recovery and tolerance to low doses of alcohol: differences in cognitive and motor skill performance. Psychopharmacology (Berl) 1979; 61: 287–91. 7. Johnson R. A., Noll E. C., Rodney W. M. Survival after a serum ethanol concentration of 11/2%. Lancet 1982; 320: 1394. 8. Jones A. W. The drunkest drinking driver in Sweden: blood alcohol concentration 0.545% w/v. J Stud Alcohol 1999; 60: 400–6. 9. Hammond K. B., Rumack B. H., Rodgerson D. O. Blood ethanol. A report of unusually high levels in a living patient. JAMA 1973; 226: 63–4. 10. Lindblad B., Olsson R. Unusually high levels of blood alcohol? JAMA 1976; 236: 1600–2. © 2013 Society for the Study of Addiction
11. Minoin G. E., Slovis C. M., Boutiette L. Severe alcohol intoxication: a study of 204 consecutive patients. J Toxicol Clin Toxicol 1989; 27: 375–84. 12. Perper J. A., Twerski A., Wienand J. W. Tolerance at high blood alcohol concentrations: a study of 110 cases and review of the literature. J Forensic Sci 1986; 31: 212– 21. 13. Roberts J. R., Dollard D. Alcohol levels do not accurately predict physical or mental impairment in ethanol-tolerant subjects: relevance to emergency medicine and dram ship laws. J Med Toxicol 2010; 6: 438–42. 14. Watanabe A., Kobayashi M., Hobara N., Nakatsukasa H., Nagashima H., Fujimoto A. A report of unusually high blood ethanol and acetaldehyde levels in two surviving patients. Alcohol Clin Exp Res 1985; 9: 14–6. 15. Dafters R., Anderson G. Conditioned tolerance to the tachycardia effect of ethanol in humans. Psychopharmacology (Berl) 1982; 78: 365–7. 16. McCusker C. G., Brown K. Alcohol-predictive cues enhance tolerance to and precipitate ‘craving’ for alcohol in social drinkers. J Stud Alcohol 1990; 51: 494–9. 17. Mansfield J. G., Cunningham C. L. Conditioning and extinction of tolerance to the hypothermic effect of ethanol in rats. J Comp Physiol Psychol 1980; 94: 962–9. 18. Melchior C. L. Conditioned tolerance provides protection against ethanol lethality. Pharmacol Biochem Behav 1990; 37: 205–6. 19. Vogel-Sprott M. D., Rawana E., Webster R. Mental rehearsal of a task under ethanol facilitates tolerance. Pharmacol Biochem Behav 1984; 21: 329–31. 20. Larson S. J., Siegel S. Learning and tolerance to the ataxic effect of ethanol. Pharmacol Biochem Behav 1998; 61: 131–42. 21. Siegel S., Sdao-Jarvie K. Attenuation of ethanol tolerance by a novel stimulus. Psychopharmacology (Berl) 1986; 88: 258–61. 22. Langenbucher J., Nathan P. E. Psychology, public policy, and the evidence for alcohol intoxication. Am Psychol 1983; 38: 1070–7. 23. Gentilello L. M., Villaveces A., Reis R. R., Nason K. S., Daranciang E., Donovan D. M. et al. Detection of acute alcohol intoxication and chronic alcohol dependence by trauma center staff. J Trauma 1999; 47: 1131–5. 24. Perham N., Moore S. C., Shepherd J., Cusens B. Identifying drunkenness in the night-time economy. Addiction 2007; 102: 377–80. 25. McGuire F. L. The accuracy of estimating the sobriety of drinking drivers. J Safety Res 1986; 17: 81–5. 26. Teplin L. A., Lutz G. W. Measuring alcohol intoxication: the development, reliability and validity of an observational instrument. J Stud Alcohol 1985; 46: 459–66. 27. Sullivan J. B., Hauptman M., Bronstein A. C. Lack of observable intoxication in humans with high plasma alcohol concentrations. J Forensic Sci 1987; 32: 1660–5. 28. Olsen K. N., Smith S. W., Kloss J. S., Ho J. D., Apple F. S. Relationship between blood alcohol concentration and observable symptoms of intoxication in patients presenting to an emergency department. Alcohol Alcohol 2013; 48: 386–9. 29. Brennan I., Moore S. C., Byrne E., Murphy S. Interventions for disorder and severe intoxication in and around premises, 1989–2009. Addiction 2011; 106: 706–13. 30. Brick J., Carpenter J. A. The identification of alcohol intoxication by police. Alcohol Clin Exp Res 2001; 25: 850–5. Addiction, 109, 851–854
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Letters to the Editor
31. Carroll N., Rosenberg H., Funke S. Recognition of intoxication by alcohol counselors. J Subst Abuse Treat 1988; 5: 239–46. 32. Wells J. K., Greene M. A., Foss R. D., Ferguson S. A., Williams A. F. Drinking drivers missed at sobriety checkpoints. J Stud Alcohol 1997; 58: 513–7. 33. Rubenzer S. Judging intoxication. Behav Sci Law 2011; 29: 116–37.
RESPONSE TO LETTER FROM BARRY & DENNIS We are grateful for the letter from Barry & Dennis [1] because it helps to clarify the kind of measurement validation needed to support enforcement of laws prohibiting service to intoxicated bar patrons. In fact, although in our paper [2] we discuss the development and validation of a measure of intoxication based on observable signs, addressing drunkenness of bar patrons does not require a measure that is valid across the spectrum of levels of consumption—the only validation issue for the enforcement approach we are proposing is that if someone is identified as being very drunk, they actually are very drunk. In particular, when enforcing laws against overserving, enforcement agents are often put into the position of having to prove, after the fact, that the patron who was served was, in fact, intoxicated. Without this proof, the charge against the licensee is often dropped, leading to frustration on the part of enforcement agents and ultimately a lack of enforcement. One way around this, as we suggest in the paper, is to set the threshold quite high using gross signs of intoxication (e.g. staggering, slurring words, losing balance) to increase specificity (i.e. so that no non-intoxicated people are identified erroneously as intoxicated). This will, of course, result in reduced sensitivity (i.e. more false negatives); however, that some people who have high blood alcohol concentrations (BACs) may not be identified as visibly intoxicated is irrelevant—to make the charge stick, it is only necessary to show that the person identified as intoxicated was, in fact, intoxicated. With current technology, such observable criteria could easily be backed by video recording of the person’s behaviour. The arguments by Barry & Dennis regarding why intoxication cannot be measured reliably based on observable signs relate almost entirely to the fact that people who have high BACs may not appear to be intoxicated, thereby resulting in false negatives. Brick & Erickson [3] were also concerned with this problem— that is, misinterpreting people as being less intoxicated than they actually are—and the inherent risks this poses for safe driving. This is a very important concern for preventing drinking and driving, because such individuals are likely to have significant impairment when © 2014 Society for the Study of Addiction
853
they drive despite the lack of overt signs of intoxication. Thus, we agree entirely with Barry & Dennis that some people who have consumed large amounts of alcohol may indeed appear quite sober because of individual differences and the tolerance they have developed. However, the main concern in terms of intoxication of bar patrons is identifying patrons who are obviously intoxicated. Failing to identify people as being intoxicated because they are well behaved and not showing any visible signs of intoxication (despite high BACs) is of much less concern. Existing laws regarding serving intoxicated patrons are rarely, if ever, enforced and it is unlikely that random breath checks will ever be implemented to address simple intoxication. Therefore, we disagree with Barry & Dennis that setting a threshold for intoxication based on observable criteria could ‘serve as a hindrance’ to building future initiatives to prevent intoxication. If this approach can result in systematic and successful enforcement of serving laws, at least for the most obviously drunk, this would be a substantial step forward from the current situation.
Declaration of interests In the past 5 years, the Centre for Public Health (M.A.B., K.H.) has received a grant from Drinkaware to undertake an independent study of drinking behaviours among students and M.A.B. has provided them with independent medical advice. Drinkaware is an independent UK-wide charity supported by voluntary contributions from the alcohol and supermarket industries and governed through a memorandum of understanding between the Department of Health, Home Office, Scottish Executive, Welsh Assembly Government, Northern Ireland Office and Portman Group. There are no other conflicts of interest. KATHRYN GRAHAM 1,2,3,4, PETER MILLER 1,4,5, TANYA CHIKRITZHS 1,4, MARK A. BELLIS 6, JOHN D. CLAPP 7, KAREN HUGHES 6, TRACI L. TOOMEY 8 & SAMANTHA WELLS 1,2,3
Centre for Addiction and Mental Health, London, ON, Canada N6G 4X8,1 Western University, London, ON, Canada,2 Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada,3 National Drug Research Institute, Curtin University, Perth, WA, Australia,4 School of Psychology, Deakin University, Geelong, Vic., Australia,5 Centre for Public Health, Liverpool John Moores University, Liverpool, UK,6 College of Social Work, The Ohio State University, Columbus, OH7 and School of Public Health, University of Minnesota, Minneapolis, MN, USA8. E-mail: [email protected] Addiction, 109, 851–854
This document is a scanned copy of a printed document. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material.
Letters to the Editor The journal publishes both invited and unsolicited letters.
METHODOLOGICAL AND PRACTICAL LIMITATIONS TO VISUALLY DETERMINING INTOXICATION In response to Graham et al.’s [1] recent contribution entitled ‘Reducing intoxication among bar patrons: some lessons from prevention of drinking and driving’, we would like to highlight a sample of the salient methodological and practical pitfalls associated with developing a ‘valid and reliable measure of intoxication based on observable behavior’ (p. 697). For a more detailed discussion and contextualization of these limitations, we recommend that interested readers consult Brick & Erickson [2]. Tolerance Simply stated, functional tolerance occurs when the brain adapts, and begins to compensate for, the influence of alcohol on both bodily function and behavior [3]. That said, development of functional tolerance occurs at different rates for the various psychomotor functions, cognitive tasks and bodily functions that are impacted by alcohol [4–6]. Chronic alcohol users can reach blood alcohol concentration (BAC) levels that may incapacitate or kill others (i.e. BACs ≥ 400–500 mg/dl), while at the same time masking the accompanying visual signs of intoxication that less experienced drinkers may exhibit [7–14]. Thus, visually determining intoxication is dependent not only upon (i) the individual characteristics of the patron, but also (ii) the task being observed and (iii) the tolerance level of the person performing the tasks. To further complicate visual identification of intoxication, it is noteworthy that tolerance can be both (i) dependent upon the setting in which the behaviour occurs and (ii) learned. Tolerance to the effects of alcohol can be accelerated if alcohol is consumed within the same environmental context, or accompanied by the same external stimuli [3,15–18]. Additionally, if tasks are practised while drinking, it is possible that tolerance can be learned or behaviorally augmented [3]. In other words, ‘development of ethanol tolerance is sensitive to the same training procedures which facilitate drug-free learning of a task’ ([19], p. 329). Tolerance associated with a specific context/environment or a certain task, however, is not transferrable to novel stimuli or unpractised conditions [20,21]. Sensitivity and specificity Depending upon the outcome of interest, there are varying levels of acceptable sensitivity and specificity. © 2013 Society for the Study of Addiction
Unfortunately, the current evidence-base suggests that a visual test for intoxication would lack high rates of either. For instance, after watching a target enter a room, sit in a chair, engage in a standard interview and subsequently exit, four groups of social drinkers were asked to rate four different targets on level of intoxication [i.e. sober, moderately intoxicated (50 mg/dl), or very intoxicated/legally drunk (100 mg/dl)]. Only four of the 16 categorical assessments were accurate, none of which included the legally intoxicated targets [22]. Physicians’ and emergency nurses’ ability to detect acute alcohol intoxication among trauma patients has also exhibited poor sensitivity (23% of patients with a BAC > 100 mg/dl were not identified) and specificity rates (patients were more likely to be falsely classified as intoxicated if young, male, disheveled, uninsured or having a low income) [23]. While physical manifestations (i.e. staggering gait, glazed eyes, slurred speech) have demonstrated some utility in determining intoxication, these manifestations—individually and in combination—were examined at excessive intoxication levels (i.e. BAC of 0.15% and higher) [24]. That said, even at blood alcohol concentrations above 100 mg/dl, only small proportions (21%) of drivers (n = 1115) were identified correctly as intoxicated [25]. Thus, among average drinkers, ‘signs of visible intoxication are not readily observed at BACs that currently define intoxicated driving (80 md/dl)’ ([2], p. 1498). When considering chronic drinkers specifically, ‘at BACs of less than the 150 mg/dl range, most (i.e. >50%) will not appear visibly intoxicated’ ([2], p. 1498). Previous attempts to establish an observational instrument It is noteworthy that an observational instrument designed to assess alcohol intoxication visually, the 11-item Alcohol Symptom Checklist (ASC), has already been developed [26]. Developers of the ASC contend that initial psychometric testing confirms ‘the scale’s reliability, its interrater consistency, and its predictive validity’ ([26], p. 459). Subsequent evaluation and testing, however, documented exceedingly low correlations between the ASC ratings and a plasma alcohol concentration [27]. More recent testing of the ASC with patients presenting at an emergency department confirmed the questionable utility of observational instruments, concluding that ‘outward physical signs of intoxication do not correlate well with BACs as measured by alcohol testing’ ([28], p. 4). Addiction, 109, 851–854
bs_bs_banner
852
Letters to the Editor
Overall, there is limited evidence that current premiselevel interventions will reduce intoxication [29]. Thus, as Graham et al. [1] assert, rethinking our approach to reducing patron intoxication levels is both necessary and recommended. Unfortunately, the ability to detect alcohol intoxication visually, even among trained professionals such as police officers, physicians and alcohol counselors, has been erratic at best (2,22,23,30–32). Inability to reliably assess intoxication visually is due to the fact that ‘no behavioral or physical sign has emerged that is consistently related to a specific level of BAC without large variation among individuals’ ([33], p. 134). Given this constellation of factors, building future initiatives on the unreliable shifting sands of subjective determinations of visual intoxication does nothing to further future research efforts and may, in fact, serve as a hindrance. Declaration of interests None. ADAM E. BARRY 1 & MAURICE E. DENNIS 2
Department of Health Education and Behavior, University of Florida, Gainesville, FL 32611, USA1 and Texas A&M Traffic Institute, College Station, TX, USA2. E-mail: [email protected] References 1. Graham K., Miller P., Chikritzhs T., Bellis M. A., Clapp J. D., Hughes K. et al. Reducing intoxication among bar patrons: some lessons from prevention of drinking and driving. Addiction 2014; 109: 693–8. 2. Brick J., Erickson C. K. Intoxication is not always visible: an unrecognized prevention challenge. Alcohol Clin Exp Res 2009; 33: 1489–507. 3. National Institutes on Alcohol Abuse and Alcoholism. Alcohol and tolerance. Alcohol Alert 1995; 28: PH 356. 4. Pohorecky L. A., Brick J., Carpenter J. A. Assessment of the development of tolerance to ethanol using multiple measures. Alcohol Clin Exp Res 1986; 10: 616–22. 5. Tabakoff B., Kiianmaa K. Does tolerance develop to the activating, as well as the depressant, effects of ethanol? Pharmacol Biochem Behav 1982; 17: 1073–6. 6. Vogel-Sprott M. D. Acute recovery and tolerance to low doses of alcohol: differences in cognitive and motor skill performance. Psychopharmacology (Berl) 1979; 61: 287–91. 7. Johnson R. A., Noll E. C., Rodney W. M. Survival after a serum ethanol concentration of 11/2%. Lancet 1982; 320: 1394. 8. Jones A. W. The drunkest drinking driver in Sweden: blood alcohol concentration 0.545% w/v. J Stud Alcohol 1999; 60: 400–6. 9. Hammond K. B., Rumack B. H., Rodgerson D. O. Blood ethanol. A report of unusually high levels in a living patient. JAMA 1973; 226: 63–4. 10. Lindblad B., Olsson R. Unusually high levels of blood alcohol? JAMA 1976; 236: 1600–2. © 2013 Society for the Study of Addiction
11. Minoin G. E., Slovis C. M., Boutiette L. Severe alcohol intoxication: a study of 204 consecutive patients. J Toxicol Clin Toxicol 1989; 27: 375–84. 12. Perper J. A., Twerski A., Wienand J. W. Tolerance at high blood alcohol concentrations: a study of 110 cases and review of the literature. J Forensic Sci 1986; 31: 212– 21. 13. Roberts J. R., Dollard D. Alcohol levels do not accurately predict physical or mental impairment in ethanol-tolerant subjects: relevance to emergency medicine and dram ship laws. J Med Toxicol 2010; 6: 438–42. 14. Watanabe A., Kobayashi M., Hobara N., Nakatsukasa H., Nagashima H., Fujimoto A. A report of unusually high blood ethanol and acetaldehyde levels in two surviving patients. Alcohol Clin Exp Res 1985; 9: 14–6. 15. Dafters R., Anderson G. Conditioned tolerance to the tachycardia effect of ethanol in humans. Psychopharmacology (Berl) 1982; 78: 365–7. 16. McCusker C. G., Brown K. Alcohol-predictive cues enhance tolerance to and precipitate ‘craving’ for alcohol in social drinkers. J Stud Alcohol 1990; 51: 494–9. 17. Mansfield J. G., Cunningham C. L. Conditioning and extinction of tolerance to the hypothermic effect of ethanol in rats. J Comp Physiol Psychol 1980; 94: 962–9. 18. Melchior C. L. Conditioned tolerance provides protection against ethanol lethality. Pharmacol Biochem Behav 1990; 37: 205–6. 19. Vogel-Sprott M. D., Rawana E., Webster R. Mental rehearsal of a task under ethanol facilitates tolerance. Pharmacol Biochem Behav 1984; 21: 329–31. 20. Larson S. J., Siegel S. Learning and tolerance to the ataxic effect of ethanol. Pharmacol Biochem Behav 1998; 61: 131–42. 21. Siegel S., Sdao-Jarvie K. Attenuation of ethanol tolerance by a novel stimulus. Psychopharmacology (Berl) 1986; 88: 258–61. 22. Langenbucher J., Nathan P. E. Psychology, public policy, and the evidence for alcohol intoxication. Am Psychol 1983; 38: 1070–7. 23. Gentilello L. M., Villaveces A., Reis R. R., Nason K. S., Daranciang E., Donovan D. M. et al. Detection of acute alcohol intoxication and chronic alcohol dependence by trauma center staff. J Trauma 1999; 47: 1131–5. 24. Perham N., Moore S. C., Shepherd J., Cusens B. Identifying drunkenness in the night-time economy. Addiction 2007; 102: 377–80. 25. McGuire F. L. The accuracy of estimating the sobriety of drinking drivers. J Safety Res 1986; 17: 81–5. 26. Teplin L. A., Lutz G. W. Measuring alcohol intoxication: the development, reliability and validity of an observational instrument. J Stud Alcohol 1985; 46: 459–66. 27. Sullivan J. B., Hauptman M., Bronstein A. C. Lack of observable intoxication in humans with high plasma alcohol concentrations. J Forensic Sci 1987; 32: 1660–5. 28. Olsen K. N., Smith S. W., Kloss J. S., Ho J. D., Apple F. S. Relationship between blood alcohol concentration and observable symptoms of intoxication in patients presenting to an emergency department. Alcohol Alcohol 2013; 48: 386–9. 29. Brennan I., Moore S. C., Byrne E., Murphy S. Interventions for disorder and severe intoxication in and around premises, 1989–2009. Addiction 2011; 106: 706–13. 30. Brick J., Carpenter J. A. The identification of alcohol intoxication by police. Alcohol Clin Exp Res 2001; 25: 850–5. Addiction, 109, 851–854
bs_bs_banner
Letters to the Editor
31. Carroll N., Rosenberg H., Funke S. Recognition of intoxication by alcohol counselors. J Subst Abuse Treat 1988; 5: 239–46. 32. Wells J. K., Greene M. A., Foss R. D., Ferguson S. A., Williams A. F. Drinking drivers missed at sobriety checkpoints. J Stud Alcohol 1997; 58: 513–7. 33. Rubenzer S. Judging intoxication. Behav Sci Law 2011; 29: 116–37.
RESPONSE TO LETTER FROM BARRY & DENNIS We are grateful for the letter from Barry & Dennis [1] because it helps to clarify the kind of measurement validation needed to support enforcement of laws prohibiting service to intoxicated bar patrons. In fact, although in our paper [2] we discuss the development and validation of a measure of intoxication based on observable signs, addressing drunkenness of bar patrons does not require a measure that is valid across the spectrum of levels of consumption—the only validation issue for the enforcement approach we are proposing is that if someone is identified as being very drunk, they actually are very drunk. In particular, when enforcing laws against overserving, enforcement agents are often put into the position of having to prove, after the fact, that the patron who was served was, in fact, intoxicated. Without this proof, the charge against the licensee is often dropped, leading to frustration on the part of enforcement agents and ultimately a lack of enforcement. One way around this, as we suggest in the paper, is to set the threshold quite high using gross signs of intoxication (e.g. staggering, slurring words, losing balance) to increase specificity (i.e. so that no non-intoxicated people are identified erroneously as intoxicated). This will, of course, result in reduced sensitivity (i.e. more false negatives); however, that some people who have high blood alcohol concentrations (BACs) may not be identified as visibly intoxicated is irrelevant—to make the charge stick, it is only necessary to show that the person identified as intoxicated was, in fact, intoxicated. With current technology, such observable criteria could easily be backed by video recording of the person’s behaviour. The arguments by Barry & Dennis regarding why intoxication cannot be measured reliably based on observable signs relate almost entirely to the fact that people who have high BACs may not appear to be intoxicated, thereby resulting in false negatives. Brick & Erickson [3] were also concerned with this problem— that is, misinterpreting people as being less intoxicated than they actually are—and the inherent risks this poses for safe driving. This is a very important concern for preventing drinking and driving, because such individuals are likely to have significant impairment when © 2014 Society for the Study of Addiction
853
they drive despite the lack of overt signs of intoxication. Thus, we agree entirely with Barry & Dennis that some people who have consumed large amounts of alcohol may indeed appear quite sober because of individual differences and the tolerance they have developed. However, the main concern in terms of intoxication of bar patrons is identifying patrons who are obviously intoxicated. Failing to identify people as being intoxicated because they are well behaved and not showing any visible signs of intoxication (despite high BACs) is of much less concern. Existing laws regarding serving intoxicated patrons are rarely, if ever, enforced and it is unlikely that random breath checks will ever be implemented to address simple intoxication. Therefore, we disagree with Barry & Dennis that setting a threshold for intoxication based on observable criteria could ‘serve as a hindrance’ to building future initiatives to prevent intoxication. If this approach can result in systematic and successful enforcement of serving laws, at least for the most obviously drunk, this would be a substantial step forward from the current situation.
Declaration of interests In the past 5 years, the Centre for Public Health (M.A.B., K.H.) has received a grant from Drinkaware to undertake an independent study of drinking behaviours among students and M.A.B. has provided them with independent medical advice. Drinkaware is an independent UK-wide charity supported by voluntary contributions from the alcohol and supermarket industries and governed through a memorandum of understanding between the Department of Health, Home Office, Scottish Executive, Welsh Assembly Government, Northern Ireland Office and Portman Group. There are no other conflicts of interest. KATHRYN GRAHAM 1,2,3,4, PETER MILLER 1,4,5, TANYA CHIKRITZHS 1,4, MARK A. BELLIS 6, JOHN D. CLAPP 7, KAREN HUGHES 6, TRACI L. TOOMEY 8 & SAMANTHA WELLS 1,2,3
Centre for Addiction and Mental Health, London, ON, Canada N6G 4X8,1 Western University, London, ON, Canada,2 Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada,3 National Drug Research Institute, Curtin University, Perth, WA, Australia,4 School of Psychology, Deakin University, Geelong, Vic., Australia,5 Centre for Public Health, Liverpool John Moores University, Liverpool, UK,6 College of Social Work, The Ohio State University, Columbus, OH7 and School of Public Health, University of Minnesota, Minneapolis, MN, USA8. E-mail: [email protected] Addiction, 109, 851–854
This document is a scanned copy of a printed document. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material.
