Vivid dreams are not at all uncommon on NRT, steroids and some medications. Some people report having out of body experiences as well. The nicotine molecule attaches to the same receptors in your brain as acetylcholine, a neurotransmitter which is tied in to memory and learning. The first time I went on patches, I got a full body tingly/numb feeling and had really bizarre dreams nightly. I am not a doctor/scientist but I think to much nicotine or a sharp withdrawl from it can upset the balance of what the body is used to and have effects directly on the neurotransmitters. Most of us have a "stasis" level of nicotine we are used to per day. Changing to an e-cig may change that level to either higher or lower. The body normally adapts though and you go back in to balance. If you are having symptoms of too much nicotine, it is best to back off a bit though
Slither, I think you are correct here. But I think there is more to it. Nic does activate acetyl choline receptors, and will increase dreams as a result. However, analogs have MAOIs in them which are
anticholinergic, and so balance this for the smoker. Remove those (vaping) and its all nic, plus the withdrawal cholinergic effects of no MAOIs, such as dreams and constipation. I had these in the beginning too. But they have for the most part gone away now.
I find the nature of the dreams themselves is very interesting here. One can take choline supplements to boost memory...it works, and also boosts math abilities, but too much can make you a bit spaced out. Triple strength lecithin is high in phosatidyl choline, and will do this. It boosts brain-levels of acetylcholine. I've known people in the sciences that have used this for boosting memory and math thinking...until the dreams start. We called them "choline dreams". High energy, adventurous, apocalyptic, with running away from something, or fighting something. A couple dreams like this is ok, but when they come every night it gets very old. The choline dreams are why I don't take lecithin anymore.
Nic lights up all the acetylcholine, higher thinking, pathways. MaOIs partially shut these pathways down. Remove the MAOIs, and keep the nic level high or higher than when smoking, and presto: choline dreams. Crazy action movie high-energy choline dreams. Color is also amplified, as are other senses. And the memory of the dreams lasts longer too.
They will most likely pass. I don't have then nearly as often as in the beginning.