I read your follow up post, indicating you do take 60 mg Adderall daily, which is, frankly, a fairly large dose of amphetamines, especially to dose daily. I am not saying whether or not it is worth taking as you are, because I do not know your personal situation, but I can say that amphetamines can, quite obviously, cause issues with sleep. Adderall, containing about a quarter levoamphetamine, and about three-quarters dextroamphetamine, has the potential to cause insomnia more so than other amphetamines, as the levoamphetamine has a bit longer half-life than the dextroamphetamine, and while it does not do much with the CNS, it does a lot with the PNS (peripheral nervous system) by keeping it stimulated. The PNS stimulation can be felt, and some find it unplesant, but some find it helpful in assisting the dextroamphetamine to stimulate the body and mind by giving an extra "umph" if you will of energy. It is worth considering, perhaps, switching to Dexedrine IR or Dexedrine Spansule, or Vyvanse. If you find that you need the Adderall for "energy" more than anything, and you are often fatigued, it might be wise to stay on the Adderall. If it simply helps you with troubles you have with mood, concentration of focus, attention etc., a pure dextroamphetamine choice might be better, or Vyvanse which metabolizes into dextroamphetamine and can yield good results. It might leave you with very similar therapeutic effects, but if there are any side-effects, they would likely diminish. This is just an idea, not necessarily what I think would definitely be best. For example, I would not want to switch from Adderall XR, because I like the levoamphetamine's effects which are sort of "wiring" for lack of a better word. For me, it helps with my fatigue and energy levels in a way I don't think pure dextroamphetamine could as well. But, this varies, and depends on why one is using amphetamines.
Back to hypnotics, though, I would suggest you do try melatonin. There is little reason not to do so, and it really can be of help for those with insomnia. I might also suggest you look into what I mentioned in my first post. I am beginning to think Xanax (alprazolam) might be not such a bad idea, but to use this as a hypnotic with success varies from person to person. It does hit quickly and "hard" with good anxiolysis (anxiety relief), and is very good for panic attacks, too. It's half-life and duration of action are relatively fairly short, a bit shorter than lorazepam's, for example. I have known people, firsthand, who have said it does help with sleep and have taken it nightly for insomnia. If you do suffer PTSD, this might be a good option for you to take at night for sleep, but dose carefully, for you don't want to jack up your tolerance to unwanted levels. I would say start with maybe 0.5 mg + melatonin (probably 3 mg), and if you feel the need to up the dose, don't just jump to 1 mg nightly, but go to 0.75 mg first. I still think Doral (quazepam) should be explored, though. I see it having potential, especially due to the effects increasing with chronic dosing as the levels of the drug and its metabolites grow higher through the first few days to about a week, exerting its strongest effect after several days. This might also very well help your daytime anxiety related to the PTSD, or just ease out the Adderall's effects (not cancel out, of course - ease out). The thing with quazepam is that there will be that steady level that will be obtained through the nightly dosing, so it will exert effect day and night. It also is absorbed quite quickly, so you could take a little extra on particularly bad nights, of course having a script that allows that so you don't run out. I am beginning to think this is really the best option, with nightly melatonin, too. But, I do not know. Just ideas.
Oh, and Vicodin contains hydrocodone, an opiate, which as stated above, cannot really be compared against a z-drug like Lunesta.