Unlike today, most addicts, of 100 years ago, were the dregs of society ... whores, actresses, actors, dillitants, and bums. It wasn't race, it was degeneracy. The high end mistresses of the Demi Monde, used laudanum to attempt suicide or as a scare tactic ( for their lovers ) to keep / get back a rich patron. Teens weren't doing any form of dope, for the heck of it.
The high rate of morphine addiction after the Civil War contributed greatly to the problem.