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.
Yes, I do remember that now. I saw the movie, “The Last Emperor” years ago, and the one scene that sticks in my mind is of people zonked out in opium dens.