Social crowds might have a greater impact in younger adolescence, but in later adolescence the role of best friends or romantic partners become the most important influence in attitudes and behaviours, especially those health related.
There is also an increased vulnerability to addiction with age.
Research has found that around 1/3 of alcoholics develop their dependancy after retirement, suggesting that a change in lifestyle can link to the behaviour.
The increased stresses of age can also lead to addictive behaviours, such as boredom or the death of a loved one.
Support for age being a vulnerability to addiction comes from SHRAM, who found that nicotine had a greater activating effect on the brains of adolescent rats. They were also more sensitive to the rewarding effects of nicotine, but less to the adverse effects of withdrawal.
These results therefore suggest that the rewarding effects of nicotine are highest in adolescents, demonstrating how this is the primetime for the initiation of addiction.