The answer depends on whom you ask.
Just a few grains of the substance can kill.
Teenagers’ use of hard drugs, alcohol and tobacco in the US has gone down significantly in recent years.
Since 2000, the number of deaths from heroin overdose have quadrupled. At the same time, the profile of the average overdosed fatality has shifted from older back men to younger white males, according to the Centers for Disease Control and Prevention (CDC).