We were just in Aruba over the Christmas vacation period and did not find any problems with drugs around the high rise district at all. Now we are in our late 40's so we wouldn't exactly look like the type drug dealers would be seeking out!
However, our teenagers have told us in the past that if someone wanted drugs they could be found but they have never been approached. They go out at night but we instruct them to use the same judgment and caution they do at home. They do not walk along the boardwalk at 2am, they take a taxi back to the hotel for $5. We walk the boardwalk all the time at night but not late at night or the wee hours of the morning.
Aruba is very safe but you still must have common sense. Crime is everywhere but it is nothing like in the US or Canada!