Final answer:
Functional tolerance is the condition in which chronic drinkers may show few signs of impairment, even at high blood alcohol levels, because of compensatory adaptations in the brain. This is different from metabolic processes in the liver, which can also adapt but don't explain reduced signs of intoxication. A person's impairment level is initially tied to their blood alcohol concentration (BAC).
Step-by-step explanation:
Chronic drinkers may exhibit functional tolerance, showing few signs of impairment or intoxication even at high blood alcohol levels. Functional tolerance develops as a result of chronic alcohol exposure leading to compensatory adaptations in the brain's reward circuitry. Over time, more alcohol is required to achieve the same effects, and when alcohol consumption is stopped, withdrawal symptoms may occur. This tolerance to alcohol develops separately from the liver's metabolic processes, which can also adapt to increased alcohol consumption but do not explain the reduced observable signs of intoxication in chronic drinkers.
Chronic excessive alcohol consumption can lead to liver disease, as the liver is a major organ responsible for metabolizing alcohol. Yet, a person's immediate level of impairment depends on their blood alcohol concentration (BAC), which can vary between individuals due to factors such as age, sex, metabolic rate, and pre-existing health conditions.