Adolescents and adults differ in their physical and cognitive responses to alcohol. Typically, adolescents are less sensitive to the intoxicating effects of alcohol. For example, the same blood alcohol concentrations cause less sedation in adolescents than in adults.
Learn more about the intoxicating effects of alcohol and the brain areas that are affected.
In contrast adolescents are more sensitive to the memory disruption and neurotoxic effects produced by alcohol compared to adults. Detectable after only one or two drinks the severity of memory loss is proportional to the amount of alcohol ingested. In fact heavy drinking episodes can actually result in a blackout whereby a person is later unable to recall events that occurred during the time of drinking.
Interestingly, animal studies have helped us to understand these differences. For example when compared to adult rats, adolescent rats demonstrate less alcohol-induced impairments in balance and coordination (signs of intoxication) and more alcohol-induced impairments in learning and memory.
This combination of different sensitivities is rather unfortunate for the adolescent. Adolescents may drink more alcohol compared to adults and consequently achieve much higher (and more dangerous) blood alcohol concentrations (BACs) before becoming incapacitated. The higher alcohol levels that are achieved in a maturing brain increases the adolescent’s risk for neurotoxicity and memory problems.
In addition to the effects of alcohol on the adolescent brain drinking alcohol at an early age has other risks. There is extensive research to show that the earlier a person drinks alcohol in his/her life the more likely (s)he will have an alcohol use disorder as an adult. More specifically an adolescent who starts to drink alcohol before the age of 15 is 4 times more likely to develop addiction to alcohol as an adult compared to a person who starts to drink alcohol at the age of 21.
Learn more about BACs and the effects of alcohol.