Sleeping pills are a very badidea long term, I'm talking from having years of experience with dependency on zolpidem, a very similar drug to zopiclone. Both are classified as non-benzodiazepine hypnotics, but they work basically exactly the same way normal benzodiazepines do, they just have pronounced hypnotic effects and generally shorter half lives which means they don't stay in your system for as long.
This explains it pretty well:
How do benzodiazepines work?
When taken orally, benzodiazepines are absorbed in the stomach and small intestine and metabolized by the liver. Benzodiazepines are highly fat soluble and accumulate in fatty tissue.
Excretion is through sweating, saliva, urine, faeces and breast milk.
The benzodiazepines operate widely in the brain, affecting emotional reactions, memory, thinking, control of consciousness, muscle tone and coordination. The benzodiazepines enhance the action of the neurotransmitter, GABA(Gamma Amino Butyric Acid). Neurotransmitters are chemicals which enable the brain cells to transmit impulses from one to another. They are released from brain cells by electrical signals. Once released, the neurotransmitters signal inhibition or excitation of neighboring brain cells.
GABA is the major inhibitory neurotransmitter. The function of GABA is to slow or calm things down. Benzodiazepines increase the efficiency of GABA, thus causing greater inhibition or calming.
This specifically references benzodiazepines but this explanation also applies to nonbenzodiazepine drugs like zolpiclone and zolpidem.
What happens is that once your brain becomes reliant on these drugs to enhance GABA in the brain, the body begins to "down regulate" GABA production and you start to experience withdrawal effects: increased anxiety, and a whole bunch of other minor, and more serious symptoms.
So the key is to use these drugs
only when you really need to. Otherwise, the best thing to do is to find better ways to sleep.
If you haven't tried melatonin (
http://en.wikipedia.org/wiki/Melatonin), I really would suggest you give it a go. It is surprisingly very effective at inducing sleep. In comparison to other sleeping aids, it is extremely safe to use. Everyone seems to react a bit differently to it, but it does a good job at putting people to sleep - experiment with dosages, most brands recommend a standard dose of 3mg, but there are studies that indicate that lower doses can actually be more effective. It's something you need to play around with.
Other important factors in good sleep are obvious like exercise, proper sleep hygiene, etc.
If you're really struggling, Remeron does seem to get the nod of approval from many members on this board, but I would really try to work on this stuff naturally as best you can, the further you can distance yourself from being dependent on any sort of pharmaceutical, the better.
Hope I haven't scared you, and I also hope this information helps you. The main point of my post is that if you need to use something like zolpiclone to sleep, make sure that you only use it when you need it. It's very easy to fall into a habit of using it every night and then things spiral from there.
The upside of using nonbenzodiazpeines to sleep is that it takes a lot longer for dependency to set in in comparison to standard benzos like valium, xanax, clonazepam, etc. And withdrawals are usually no where near as bad. But it's still something to keep in the back of your mind and watch out for. Also another quick recommendation I can make, from my own experience with zolpidem, is that you should try using lower doses. For example, the standard dose for zolpidem is 10mg per night, when I first started using the drug, I could get to sleep using a quarter of the pill (2.5mg). I would attempt the same with your zolpiclone, try to half or quarter it and see how you sleep. The less you use over time, the better.
Anyway, good luck buddy!