I definitely get mild visuals to full out hallucinations on heroin. If I take a bit more than I need, I tend to completely nod off into waking-dreams, and cannot open my eyes at all.
Oh mummy, last night was just awful. I had a very involving dream about being lost in a house haunted by dead little girls in blood-stained dresses. I'm really not joking, it was absolutely horrifying. They were stalking me and someone else who I was trying to help out of the place as well. I'd be running down corridors and then they'd be one of them just twitching and staggering towards me with a large pair of scissors and blood dripping down her front. HOLY SHIT!! I woke up a wreck needless to say.
I think it's all the fucking around with my methadone and valium. Which, of course, means I'll be stopping that malarky immediately.
And Creative, no, the hallucinations are basically when you slip into a 'real' event that as far as you're concerned is actually happening. The visuals are nothing like acid or any other psychs - they're as real as real gets.