Tolerance To Alcohol (cont)
Most state laws now define drunken driving by blood alcohol level, a measure which does not eliminate this subjectivity.
Dubbing such drunk driving laws " driving under the influence" or "driving while ability impaired," however, is a step in the wrong direction, Plomin cautioned. Some people are dangerously impaired below the legal blood-alcohol limit, while those with acute tolerance show almost no change at higher-than-legal levels.
The research in individual responses to alcohol, undertaken over the past six years, incorporates findings from more than 100 individuals, including siblings and identical twins. One of the long-term goals of the research is to learn more about the genetic basis of alcoholism and alcohol response.
A number of studies have concluded that alcoholics and heavy drinkers tend to develop a tolerance to the effects of alcohol. Some studies have looked at the relationship between blood-alcohol concentrations and level of consciousness — that is, the level at which an individual will lose consciousness.
Generally, individuals with BACs of .30 percent or higher begin to lapse into a stupor or coma; levels above .40 percent are usually fatal. Yet, studies are commonly reporting that individuals with histories of chronic alcohol abuse survive levels of .73 per-cent, .78 percent, 1.12 percent, and even 1.5 percent. See, respectively, Chambers, et a!., Blood Alcohol Levels, 4 Archives of Emergency Medicine 127 (1987); Hammond, et al., Blood Ethanol: A Report of Unusually High Levels in Living Patient, 226 Journal of the American Medical Association 63 (1973); Berild and Hasselbach, Survival After a Blood Alcohol Concentration 1127 mg/dl, 2 Lancet 363 (1981); Johnson, et a!., Survival After a Serum Ethanol Concentration of f 1.5%, 2 Lancet 1394 (1982).
The relevance of this information is, of course, that blood-alcohol concentration may not truly reflect an individual's degree of impairment in a non-per se drunk driving case — especially if the defendant has a history of alcohol abuse. Obviously, counsel must weigh the advantages and disadvantages of presenting evidence of a client's past alcohol abuse to a jury. Generic or hypothetical questions of an expert or officer concerning tolerance — including questions about the effects of alcohol abuse — would avoid the problem.
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