“First the Chinese smoked the drug, then the Anglo-American underworld, followed by men and women in the middle and upper classes, before finally reaching children in the community.”
Opium was imported to China by the British from India as a way to change their balance of trade with China. China insisted that everything be paid for in silver. By getting people addicted they soon began to have a trade surplus leading the Opium Wars where Britain ended up forcing China to open its markets to opium. That was actually the first war on drugs.