Thanks for all ur replys. I've only been taking half a pill a night so I think ill be okay. Just pondered this question as I have never even considered this to be a habit forming drug.
I used to take 2-3 pms a night for over a year and when I stopped I had no withdrawals surprisingly, they say that they arent addictive but i didnt believe but i really felt totally fine
That's a really low dose and you should be fine. As Eyeofhorus mentions, there may be a bit of a placebo effect working for you so don't freak out if you have trouble falling asleep a few nights.
The "PM" part of Tylenol PM is diphenhydramine, better known as Benadryl. You might experience a runny nose and sinus congestion as your body adjusts to not having that antihistamine available on a daily basis. Again, you take a low dose so those symptoms shouldn't last long if you develop them.
You might give melatonin a try for a sleep aid if you find you really need one once you've gone without the Tylenol PM for a while and still can't sleep. It's in with the vitamins and herbals at about any store that carries those items. Melatonin helps you fall asleep, but if your problem is premature awakening, you'll probably want to try the time-release version. I've only recently discovered it in a 10 mg pill and it works great for me. Have you ever talked to your doctor about your insomnia?
I've taken tylenol PM a few times to help with sleep. When life gets busy I tend run at full steam and when it gets late and I'm in no way ready for sleep yet I know I need to be up in 6 hours or so I'll take a couple to help me wind down and get to sleep. As an opiate addict I've spent too many nights wide awake and tried to work the next day.
I would catch myself getting into the habit of taking them preventively to make sure I would sleep with knowing for sure if I really needed them or not. So I wouldn't take any. I don't remember ever having a problem falling asleep after stopping. Mind you, it was less than a week at a time taking them so I can't say for sure in you case.
I would think they're having a bit of a placebo effect on your brain. When you stop you'll be certain that you can't fall asleep on your own so you may have a few sleepless nights until exhaustion takes over and then sleep will come.
I don't think you're going to experience withdrawals in the sense that you'll be sick with cramps, RLS, feverish, lethargy...etc. I think you'll just have trouble sleeping right away.
Good luck to you.
Posting off phone. Sorry so brief. :)