The most effective way to prevent teens from having later (e.g.,in adulthood) substance abuse problems is to

A) moderately punish them for any indications of interest in the problem behaviors
B) closely monitor their peer relationships
C) engage in tertiary prevention efforts
D) prevent initiation into the problem behavior in the first place

The most effective way to prevent substance abuse problems in adulthood is to prevent initiation into the problem behavior in the first place. This can be done through education, parental involvement, and limiting access to substances. Punishing teens may create resentment and rebellion, while only monitoring peer relationships may not address the root cause of the behavior. Tertiary prevention focuses on treating substance abuse problems that have already developed, rather than preventing them.