Many psychoactive substances can affect your dreams. Usually when I have fully "sober" dreams, they're mundane and ordinary (in the dream, I'll wake up and go to work and talk to my coworkers and then go home), and I generally wouldn't remember too many details after I wake up. When I took SSRIs, I'd have wilder, more vivid dreams that I remember for years. When I smoke weed heavily, I'm unlikely to dream at all and will just kinda "time-travel" to waking up.