Original RESEARCH & CONTRIBUTIONS

Special Report The Limits of Tolerance: Convicted -Impaired Drivers Share Experiences Driving Under the Influence

Sandra C Lapham, MD, MPH, FASAM

vorite hobby, biking—he owns a The National Institute on Alcohol Abstract Harley—keeps him amused on his Abuse and estimates Most people are aware that reg- days off. During his weekend for- that consuming five or more drinks ular alcohol drinkers can become ays, B stops at bars or parks along in about two hours (four or more tolerant to the effects of alcohol. the way to drink beer. B says his drinks for adult females) brings the Tolerance can lessen the outward risky behavior has lessened since BAC to 0.08% or above, the legal manifestations of intoxication, his younger days. Now he doesn’t limit for driving in all 50 states.1 and this poses challenges for drink “hard stuff” on days he rides The estimated BACs for children the drinker and other observers, his motorcycle. are different. With five drinks within including law enforcement of- two hours (the level used to define ficers. On the basis of a National among college stu- Institutes of Health-funded longi- Apparently, B assumes beer dents), children, ages 9 to 13 years, tudinal study examining a cohort is more benign than rum. In my may have BACs two to three times of convicted alcohol-impaired experience, this is a common mis- the adult legal limit for intoxication.2 drivers, this article presents com- conception among convicted drunk Several factors moderate the ab- mentary regarding this phenom- drivers. A number of offenders have sorption, distribution, and metabo- enon in offenders convicted of told me flat out that they can’t be lism of beverage alcohol. The pres- driving under the influence and alcoholics because they only drink ence of food in the stomach slows the implications for traffic safety. beer. Beer does contain less alcohol absorption. Drinking slowly and per ounce than hard liquor, and drinking more diluted alcohol al- B’s Story perhaps people mistakenly equate lows the body to metabolize it while The arrest for driving under the liquor’s quick high with addiction at the same time absorbing an in- influence (DUI) came as a surprise predilection. Beer is by far the pre- coming dose. Most people eliminate to B. Still, he took it pretty well. On ferred drink among convicted DUI about one drink each hour from one hand, he had known that he offenders, but a of a their system. An enzyme produced was breaking the law; on the other, 12-oz can of beer, a 1 ½ oz “shot” of in the stomach, glutathione-depen- he had concluded long ago that the 80-proof distilled spirits, or a 5-oz dent formaldehyde dehydrogenase, law did not apply to him. B, age 47 glass of wine all contain the same breaks down alcohol, decreasing years, is divorced, employed, and, amount of pure alcohol, 13.7 gr (0.6 its bioavailability. Alcohol is dis- unless sick, drinks a fifth of rum oz). The total amount of alcohol tributed in tissues according to most days. Drinking is important to consumed, plus other moderating water content. A person’s weight B. It calms his nerves and lifts his factors, not the type of alcoholic and sex determine the total vol- mood. Besides, he is often bored. drink, determines the blood alcohol ume of body water and, therefore, Drinking, combined with his fa- concentration (BAC). the BAC after drinking a certain

Sandra C Lapham, MD, MPH, FASAM, is a Board-Certified Specialist in Internal and . She is Director of the Behavioral Health Research Center of the Southwest, a center of the Pacific Institute for Research and Evaluation and Principal Investigator for an NIH-funded longitudinal study examining a cohort of convicted alcohol-impaired drivers. E-mail: [email protected].

26 The Permanente Journal/ Summer 2010/ Volume 14 No. 2 Original RESEARCH & CONTRIBUTIONS The Limits of Tolerance: Convicted Alcohol-Impaired Drivers Share Experiences Driving Under the Influence

amount of alcohol. In general, the ing than the descending portion of obesity, iron overload, infection, more a person weighs, the larger the BAC curve.8 Most experienced and genetic factors.12 The drinker the volume of body water and the drinkers develop some form of ac- typically is unaware of this process, lower the BAC. Alcohol pharmaco- quired or chronic tolerance. Chronic but when liver function declines kinetics differ by gender.3,4 Women tolerance is a bodily adaptation that below a certain threshold, tolerance have lower glutathione-dependent makes a person need to drink more declines. If the drinking continues, formaldehyde dehydrogenase ac- and more alcohol to get the same the drinker begins to realize that tivity, leading to increased alcohol effect, or inversely, an adaptation they can no longer continue to absorption. They also generally that causes less and less response “hold their liquor.” have a higher fat content and less to a recurring dose. There is a correlation between total body water, where ethanol The degree of tolerance, how- BAC and the drug’s behavioral and is distributed. This contributes to ever, varies both within and among emotional effects, but there is also higher BACs, an enhanced rate of individuals. How and why different considerable variability. For exam- … I was the alcohol oxidation in the liver, a people develop different manifes- ple, tolerance enables some very designated driver slower rate of gastric emptying of tations of tolerance are perplex- heavy drinkers to survive BAC lev- because my alcohol, and higher vulnerability ing.6 Metabolic tolerance refers to els considered lethal (in the range friends say I can to the toxic effects of alcohol.5 But changes in the absorption, distri- of 0.40% to 0.50%).10,13 Memorable drive better than another phenomenon, “tolerance,” bution, metabolism, and excretion patients with BACs this high have anybody when affects not only the BAC, but also of alcohol.9 These changes lead to been reported as conscious and I’m intoxicated. the body’s capacity to cope with a more rapid clearance of alcohol able to carry on conversations.10 high levels of this toxic chemical. from the body. Tolerance also oc- One report from Sweden describes curs at a cellular level in the brain a woman arrested for drunken driv- Tolerance itself (called functional tolerance), ing with a BAC of 0.55%.14 It is well known that regular which reduces signs of intoxica- drinkers, like B, develop tolerance, tion, even at high BACs. Because of T’s Story broadly defined as the ability to re- tolerance, habitual users may show It is commonly believed that peo- sist the action of a drug.6 Most peo- minimal effects of a dose that would ple who are alcohol dependent are ple, including B, are familiar with cause an intense reaction in a naïve tolerant to all the effects of alcohol, the term, “tolerance.” “I have real drinker. Whereas social drinkers and that tolerance protects a person high tolerance,” he bragged during may show clear signs of intoxication from impairment caused by alcohol his interview. “I can drive fine after at a BAC of 0.10%, such as nausea, intoxication.10 T, another person a few drinks; actually pretty good slurred speech, and lack of coordi- interviewed for my study on the even after drinking a lot.” nation, heavy drinkers at that BAC drinking and driving experiences of In effect, drink for drink, B feels may not show these signs.10 Added DUI offenders, fits this description. less drunk and may have less alco- to this, some drinkers are simply “Usually I was the designated hol-induced impairment in speech, less sensitive, by nature, to alcohol’s driver because my friends say I gait, and fine and gross coordina- effects.11 This is characteristic of can drive better than anybody tion than his light-drinking coun- people with . when I’m intoxicated. Other terparts. The biologic mechanisms Learned expectancies and Pavlovian people, five beers and they’re of tolerance are complex. Different conditioning also influence toler- slurring their words or some- forms of tolerance have different ance to alcohol’s effects.10 thing, but five beers is nothing mechanisms of action. Far from be- Still, tolerance has its own limi- to me. Even when I first started ing a simple homeostatic response tations, for as the drinking career drinking, I could drink a 12- to the presence of alcohol in the progresses, over days, years and pack before I felt much effect brain, tolerance can develop within decades, so does liver damage from from the alcohol.” various time frames.7 Acute toler- alcohol’s toxic effects. Factors that ance, also called “tachyphylaxis,” may affect the development of liver Driving Under happens within a single drinking injury include the dose, duration, the Influence episode. In acute tolerance, signs and type of alcohol consumed, Both B and T fail to grasp the of intoxication at the same BAC are drinking patterns, gender, ethnic- limitations of their alcohol toler- more pronounced on the ascend- ity, and other risk factors, such as ance. Alcohol’s detrimental effects

The Permanente Journal/ Summer 2010/ Volume 14 No. 2 27 Original RESEARCH & CONTRIBUTIONS The Limits of Tolerance: Convicted Alcohol-Impaired Drivers Share Experiences Driving Under the Influence

on vision, vigilance, hand-eye co- nice guy, well thought of by friends with judges and prosecutors who ordination, anticipatory judgments, and relatives. On a warm Sunday are trained in adjudicating DUI balance, gait, mental alertness, afternoon, O enjoyed a backyard cases; community-based health problem-solving ability, estimates barbecue with friends and their care interventions for alcohol-use of distance, and quick reaction families in Santa Fe, NM. He left disorders within medical facilities to unexpected hazards are well the party around 11:30 pm. About and community settings; com- documented.6,15 Driving combines midnight he was seen driving his munity outreach and education a complex range of physical and Jeep west in the eastbound lane regarding impaired driving; and, mental activities, and all are ad- of Old Las Vegas Highway and above all, active and highly visible versely affected by alcohol. collided with a vehicle driven by law enforcement. Epidemiologic studies show A. She and four other high school Tolerance poses a significant that virtually all drivers with girls were part of a caravan heading challenge for law enforcement. BACs above 0.08% to 0.10% are to a friend’s house. According to a Signs of intoxication are easy to significantly more likely than so- witness, A tried to avoid hitting the overlook, even when you are look- ber drivers to cause a fatal motor Jeep by swerving to the left, and ing. A recent review23 of three ex- vehicle crash. In landmark stud- crossing the center lane.21 When perimental studies on the ability to ies, Paul Zador calculated relative O tried to get back into the correct detect visible intoxication concludes risks of fatal crash involvement lane, he allegedly rammed A’s car that social drinkers, bartenders, and at various BACs.16,17 The analyses broadside. The entire passenger most police officers misjudge the used data on driver fatalities in side of the victim’s car was crushed, target’s level of intoxication about single-vehicle crashes from the killing all of A’s passengers. Blood 75% of the time.10,23 The inability to national Fatality Analysis Report- tests later revealed O’s BAC was accurately judge visible impairment ing System,18 in conjunction with 0.16%, twice the legal limit for shields intoxicated drivers from de- driver exposure data from the intoxicated driving. The mug shot tection, for US law does not allow national Roadside Breathtesting taken after the incident showed O officers to pull over and test the Survey.19 Zador estimates that grinning. He may not have felt very BAC of drivers without probable each increase of 0.02% in the drunk, but his inappropriate smile cause. A recent case appealed to BAC of a driver with non-zero revealed alcohol’s betrayal. the Supreme Court draws atten- BAC nearly doubles the risk of a O’s friends from the gather- tion to this predicament.24 Police fatal crash. Crash risk rises with ing were dumbfounded. “He was in Richmond, VA, stopped a sus- increasing BAC among all of the fine,” his friend said, “He hugged pected drunk driver when a con- age and sex groups studied. At my children, myself, and he was cerned citizen reported his partial BACs in the 0.05% to 0.09% range, fine.” Another friend told police license plate number and driver the likelihood of a crash is at least that O wasn’t drunk and that was description. When stopped, the nine times greater than at zero 30 minutes before the accident.22 driver had slurred speech, watery BAC for all age groups. At very The oft-quoted admonition, “friends eyes, and exited his vehicle with high BACs (at or above 0.15%), don’t let friends drive drunk,” begs difficulty. He subsequently failed the risk of crashing is 300 to 600 the question, how can friends tell the tests, was arrested, times the risk at zero or near-zero if their friends are drunk? Tolerance and later was convicted of DUI. BACs. Younger drivers with BACs cons many an observer. The Virginia Supreme Court threw in the 0.05% to 0.09% range have out the conviction because the higher relative risks than older Law Enforcement arresting officer did not observe drivers because of immaturity, Challenge erratic or unlawful driving. This lack of tolerance to alcohol’s ef- Effective initiatives to reduce driver, who had previous DUI fects, driver inexperience, and alcohol-related traffic injury and convictions and was undoubtedly risk-taking propensity.20 death are most likely to have a tolerant to alcohol’s effects, main- positive effect if they are compre- tained his driving lane with the O’s Story hensive and community-focused. police on his tail. In other words, Tolerance may have duped O Such programs include: community there was no probable cause. The into believing he was fine to drive. collaboration, coordination, plan- US Supreme Court subsequently O, age 26 years, is described as a ning, and evaluation; court systems declined to hear the case.25

28 The Permanente Journal/ Summer 2010/ Volume 14 No. 2 Original RESEARCH & CONTRIBUTIONS The Limits of Tolerance: Convicted Alcohol-Impaired Drivers Share Experiences Driving Under the Influence

Besides citizen call-ins, sobriety M’s Story I’m the designated driver.’ I must checkpoints comprise another Does a failure to detect and ar- have been talking real good, so widespread law enforcement mea- rest impaired drivers at checkpoints he let me go. That would have sure that may be thwarted by toler- send the message that they are been my second [DUI]. At that ance. Checkpoints, conducted in immune to arrest? Perhaps. Across moment I said to myself, ‘No I 38 states, are roadblocks set up by the board, though, the participants gotta quit this.’ I’m not taking law enforcement agents to make in my study report they fear check- those chances.” the public aware of the DUI laws, points, even when they dodge the She quit drinking. and to detect and detain impaired arrest. One subject described her drivers. These roadblocks are DUI history this way: Conclusion an effective anti-DUI measure. “I was going out every night People who drink regu- The Centers for Disease Control to the bars drinking. It was an larly may find they need to Alcohol- reviewed 23 scientifically sound everyday thing for a couple of drink more and more to impaired studies from around the world on years. I’d leave the kids overnight get the same effect. This drivers are not checkpoints and concluded that with my mom, go out, and drink phenomenon, called tol- uncommonly they reduce alcohol-related crash- and go dancing. This guy would erance, is well described, passed over at es, typically by about 20%.26 In con- buy our beer—there were 20 beers but incompletely under- checkpoints. ducting these checkpoints, officers on the table—and only three or stood. Tolerance reduces … officers are trained to look for signs such four of us girls. We’d drink shots, the visible signs of in- have little as open alcohol containers, drug too. By the time we left the bar toxication. This makes it opportunity paraphernalia, an odor of alcoholic we’d be really bombed. I’ve come hard for others, including to monitor beverages or other drugs, or the ad- close to accidents. About ten years friends, alcohol servers, a driver’s mission of drinking or drug use.27 ago I was drinking and I thought and law enforcement of- handling of They are also trained to look for my driving was great, but I know ficers, to determine the the vehicle or visible signs of intoxication, such now I was a lousy driver because I drinker’s level of driving observe their as fumbling fingers, slurred speech, almost hit my friend’s vehicle. We impairment. Those who behavior. inconsistent responses, bloodshot went to a second bar, and a third. experience tolerance com- eyes, and other signs of alcohol That night I got the DUI.” monly believe that since impairment. However, in tolerant After that experience, M cut back they can “hold” their alcohol, they individuals these signs may not on her partying and went out only are capable of driving safely after be obvious. about once or twice a month. She drinking. But alcohol reduces the Alcohol-impaired drivers are not recounts her attitudes regarding physical and mental dexterity re- uncommonly passed over at check- her own , and her quired for safe driving. Studies have points. At checkpoints, officers experience at a checkpoint, on one determined that the risk of causing have little opportunity to monitor of those nights: a crash rises proportionally with a driver’s handling of the vehicle “My son and daughter-in-law BAC. Even at lower BACs (0.05% or observe their behavior. If signs were staying with me, and I lent to 0.09%), the likelihood of a crash of impairment are not salient, the them the car. I told them to drive is at least nine times greater than at driver will be waved through. In me to the bar and pick me up, be- zero BAC. At very high BACs (at or one study, Wells et al28 surveyed cause I was going to be drinking. above 0.15%), the risk of crashing drivers not detained by police at Well, my son shows up drunker is 300 to 600 times the risk at zero 156 sobriety checkpoints in North than me. ‘Good Lord son!’ I said, or near-zero BACs. Carolina. They found that more ‘You know you’re not supposed than 50% of the drivers with BACs to be driving my car drunk.’ I The Long Term over 0.08% were not detained.28 took over the driving. I only had M no longer drinks. As for O, he The authors of that study recom- four or five beers that night, so is in jail awaiting trial. B and T both mend the use of passive alcohol I wasn’t drunk, but when we report they continue to drive after sensors that detect alcohol in the came to a checkpoint we both drinking. It’s been 15 years since driver’s exhalations. This evidence got scared. When they asked me their first DUI convictions. T got is probable cause to conduct field if I’d been drinking, I told him, a second conviction last year, but sobriety tests and measure BACs. ‘No, he has (pointing to my son). B has avoided further arrests. He

The Permanente Journal/ Summer 2010/ Volume 14 No. 2 29 Original article/QUALITY IMPROVEMENT The Limits of Tolerance: Convicted Alcohol-Impaired Drivers Share Experiences Driving Under the Influence

is haughty. “It’s like a video game 10. Brick J, Erickson CK. Intoxication is age, and crash risk. J Safety Res to me. If I make it home, I win. If I not always visible: an unrecognized 2008;39(3):311-9. prevention challenge. Alcohol Clin don’t, I lose. I know when I’ve had 21. Parker P. 4 teens killed, broadside Exp Res 2009 Sep;33(9):1489-507. collision occurred on Old Las Vegas too much to drink, and I don’t drive.” 11. Schuckit MA. A clinical model Highway. Albuquerque Journal I doubt it. v of genetic influences in alcohol Newspaper 2009 Jun 29;Sect A:1. dependence. J Stud Alcohol 1994 22. Parker P, Vela V. Friend of driver: Disclosure Statement Jan;55(1):5-17. ‘He was fine.’ Albuquerque Journal The author(s) have no conflicts of 12. O’Shea RS, Dasarathy S, McCullough Newspaper 2009 Jul 1;Sect A:1. interest to disclose. AJ. Alcoholic liver disease. Am J Gas- 23. Brick J, Carpenter JA. The identi- troenterol 2010 Jan;105(1):14-32. fication of by References 13. 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