The linked article stated that the impetus for the research was mainly a long-standing issue with the alcohol consumption levels of the young, so I think it's a

The linked article stated that the impetus for the research was mainly a long-standing issue with the alcohol consumption levels of the young, so I think it's an issue they consider very important and related to drugs, but they separate it as drugs and alcohol have a different social and legal stigma and thus aren't directly comparable to each other.