fyi I've been on and off vaping for almost two years. I always vape with nicotine and I would say there is absolutely no withdraw effect whatsoever. my conclusion is it has something to do with if you were a smoker before brain is fully developed your brain will rely on the substance. if you've never touched nicotine before that you will most likely not have the withdraw effect. just figured I should let you guys know what I've been experiencing.
I see a potential flaw in this hypothesis, namely that the brain is the slowest developing organ of the body and is reported to not be fully developed until around age 25. Generally speaking nicotine users start using nicotine before that age.
However, it may be possible that the nicotine on its own is not inherently addictive, or if it is addictive the addiction is more psychological than physiological. Also it is possible that the major symptoms of withdrawal that tobacco users face, when quitting, is related not so much to the nicotine as it is the other compounds in tobacco smoke or tobacco itself. This would of course explain why some vapers have reported that they cannot quit smoking entirely without use of WTA juices.
I've not smoked a pipe in over a week (and I smoked for 20+ years), the longest time I've actually been "quit". I've completely replaced smoking (so-far) with vaping and have had very few withdrawal symptoms apart from the desire to smoke on occasions. These "cravings" seem to not be related to my nicotine level as I'm using rather strong juices (24mg usually though I do have a 21mg I use in the evenings) so I believe that it may be withdrawal symptoms of the other compounds in tobacco smoke. I have also found that it is easier to use will power to slog through those "cravings" if I have nicotine, and have that nicotine in a manner of ingestion under my control (something that the patch and gum are terrible at doing).
All of that said, I stand by what I said earlier, I would not recommend vaping to an adult nonsmoker (there simply is no tobacco harm present to reduce) and if they insisted on vaping I feel that they should use 0mg juices. As for minors, well minors should not vape just like they should not smoke. But honestly the youngest vapers I've ever encountered are in their mid-twenties, all of them vape to not smoke, and I do not see a "cool factor" present to attract minors.