Behavior, human variations

It may be argued that some individuals will not lose ethical restraint regardless of the nature or intensity of an involuntary intoxication. However, even if some individuals are relatively immune to behaving badly under the influence of drugs, while others seem especially susceptible, this merely reflects human variation, a factor that complicates most research in medicine and behavioral science. The reality of human variation does not undermine the validity of the association between certain drugs and... 

Humans differ in sensitivity due to biological factors such as metabolic polymorphism, age, gender, health status, and nutritional status. These differences can be the result of genetic and/or environ-mental/behavioral influences. This intraspecies (interindividual) variation is greater in humans than in the more inbred experimental animal population. 

Based on effects caused in monkeys and rats, the following are expected in humans 20,000 ppm for 60 minutes, coma and possibly death 10,000 ppm for 30 minutes, marked incoordination 2000ppm for 5 minutes, disturbance of equilibrium. Human subjects exposed to 900-1000ppm for 20 minutes experienced light-headedness, incoordination, and impaired equilibrium transient eye irritation has also been reported at similar concentrations. Impairments in psychomotor task performance such as reaction time, perceptual speed, and manual dexterity have been demonstrated at levels around 350ppm. Other studies at similar exposure levels have failed to show any impairment, but the type of task chosen to test behavioral effects and the times at which behavioral measures were sampled during the course of exposure may explain the variations from study to study." ... 

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