Interesting replies; incidentally, I do not know too much about these things, my girlfriend is a pharmacologist and is my backup on any scientific stuff.
By the way I don't wish to cause alarm or concern, this symptom, which I regard as interesting rather than bad, is common enough in healthy people. I included a reference to exploding head syndrome because of the hilarious name and because it is a disorder which includes the symptom, but I don't think I have the disorder. I am simply more susceptible to this (I got it a lot when coming off an SSRI once)
What misty says is correct to my knowledge- and I'd add that hypnagogic and hypnopompic hallucinations are in my experience common in one who makes any change in diet, sleep pattern, drug or medicine use, and are definitely nothing to be concerned about. I would say that this is just a manifestation of a symptom listed above, that is to say, sleep disturbance.
In addition, chewing sugarfree gum before bed (not nicotine gum obviously!) has been helpful for me in this regard, my theory is that it rebalances the delicate state of the inner ear.
Another substance with the same effect is galantamine, which inhibits acetylcholine reuptake in the synapses. Nicotine actually attaches to these receptors increasing your overall level of wakefullness.
You sound like a knowledgeable practitioner of lucid dreaming to me, you might be interested that my ability to lucid dream has at least temporarily increased since using e-cigarettes, even without acetylcholine precursors (which I usually take as choline
supplements) or Calea Zacatechici which I would sometimes drink as a tea with an evening cigarette.
Also ladybug thank you for your concern; however I am not on any medication for anything, naturally if I or a loved one was on psychiatric medication I would avoid using e-cigarettes as, since as Misty mentions above nicotine is multiple agonist, a suspected monoamine oxidase inhibitor (i.e. similar to some old school antidepressants) and has some dopamine related effects. By altering the amount of nicotine you take you run the risk of interfering with your medication. The same thing is true of patches and lozenges.
