I would not say that the effects are more acute in young people. Youths usually react to smaller quantities, but there are also people who are more sensitive to caffeine. You spoke about drug interactions, which are very important to consider. I do not have any information with me, but the report on energy drinks we are currently drafting for the Government of Quebec covers interactions with caffeine. Many medications react with caffeine.
Among other things to consider, there is the case of hyperactive children who are on drugs like Ritalin. Problems can arise if they mix caffeine with their medication.