Gabapentin was mentioned by a few other peope on this thread and it's true. If a benzo. works for you, then your problem seems to be GABA- related.
It's a lot more complicated than that. GABA is one of the brain's main neurotransmitters; it has a major inhibitory function. Receptors for GABA are very common in the brain, but there are GABA(A) receptors and GABA(B) receptors, and subtypes at least for the GABA(A) receptors. Anything that attaches to any of the binding sites on any of the GABA receptors is going to have an inhibitory effect of some sort. This inhibitory effect also affects the NMDA receptors, which are the brain's main excitatory receptors. There really isn't any such thing as a GABA-related problem (except for what I describe below); instead, there are problems that respond to GABA agonists (those molecules that stimulate the GABA receptors).
One of the subtypes of the GABA(A) receptors is the benzodiazepine receptors. This is why the benzodiazepines have a calming effect. The benzodiazepine subtype is actually a physically separate subunit. If benzodiazepines are used for a long enough time, and especially at high doses (so that more of the brain's GABA(A) receptors are affected), tolerance can develop. What happens here is that the main GABA receptor withdraws into the nerve, as the constant stimulation of the benzodiazepine receptor leads the brain to think that it doesn't need as many GABA receptors. The benzodiazepine subunit is still exposed on the surface, but now it must be continually refilled with a steady supply of benzodiazepines just to maintain the status quo. Otherwise, if the benzodiazepine receptor is left empty, it acts like an excitatory receptor. This is the mechanism of benzodiazepine withdrawal, and this is the GABA-related problem I mentioned above.
If you taper off a benzodiazepine slowly, then relative few benzodiazepine subunits of the GABA(A) receptors are excitatory over any given time. As the supply of benzodiazepines gradually decreases, the main GABA receptors gradually grow back, thus restoring everything to normal. But it takes time for them to do so. That's why if you're on a large dose of benzodiazepines and quit cold turkey, you have a massive withdrawal reaction. All those empty benzodiazepine sites become excitatory, and almost nothing can shut them up except more benzodiazepines. The main GABA receptors can't be stimulated, because they've withdrawn into the nerve. However, if you taper off the benzodiazepine slowly, you give the GABA receptors a chance to grow back, and this problem doesn't develop.
If you're on a small enough dose of benzodiazepines, then the number of GABA receptors that are affected is small enough that you don't experience these problems.
Gabapentin (Neurontin) is not a true GABA agonist, despite its name; it was named before its mode of action was understood. Gabapentin actually has many different modes of action. One of them is to bind to the benzodiazepine site of the GABA(A) receptor. For this reason, taking gabapentin can make it easier to taper off benzodiazepines. If you do this, you're left with a dependency on gabapentin, but this is much easier to deal with than a dependency on benzodiazepines.
Gabapentin is an anti-epileptic drug with good sedative properties; it is Dr. Goldstein's #1 oral drug of choice for treating ME/CFS. In addition to its sedative properties, many people find it helpful for relieving anxiety. Some people find that it gives them much more energy, and some people find that it helps with all symptoms of ME/CFS. I have found gabapentin useful for all these purposes. Its effect varies for different people.
There is a supplement called phenibut that is gaba combined with another substance which i can remember, but it helps gaba cross the blood brain barrier. It works well but tolerance occurs rapidly, so i think its a once a week thing to use and can give a hangover. It also has similar problems to benzo's in that some can get addicted to it and withdrawal issues, but using sane doses and intermittent use can help avoid that?
This is basically all correct. I would just want to emphasize that it's essential not to use it on a daily basis, or else tolerance can develop within a few days. The addiction and withdrawal issues are at least as bad as benzodiazepines. But if it's used only on an occasional basis, these can be avoided.