Yes. The characters in my setting use cannabis, opium, and coca recreationally on a fairly wide scale, in addition to caffeine and alcohol. They're cheap and legal, and (except for alcohol) don't do a lot of harm unless you have to work for a living. Though I've noticed that player characters avoid cannabis and opium.
Besides recreation use, opium is used in medicine (as the tincture, laudanum), hypnotics (opium and cannabis) are used by Dreamers, psychedelics (including hash, datura, and other hallucinogens) are used by shamans, and all sorts of things are used in religico-magical ceremonies. PCs have been obliged by circumstances to take datura on occasion, but they tend to avoid it when they can.
Besides recreation use, opium is used in medicine (as the tincture, laudanum), hypnotics (opium and cannabis) are used by Dreamers, psychedelics (including hash, datura, and other hallucinogens) are used by shamans, and all sorts of things are used in religico-magical ceremonies. PCs have been obliged by circumstances to take datura on occasion, but they tend to avoid it when they can.