In response to some of your (stimulant induced?) musings, (please for the love of your_deity_here use the edit button) -
DXM allowed GBL to stay working wel
From what I have heard, GHB/GBL is pretty reliable in terms of producing effects, pleasurable or otherwise, unless dosed very frequently.(seeing as it's an endogenous n/t and all). 1-3x a day is probably nothing to worry about. I guess it varies between people.
G gives me abscence seizures at every dose.
*Every* dose? And is it an absence seizure you're experiencing, or simply somnolence/"microsleeps"? GHB is a known & powerful inducer of sleep in many individuals.
From what I have heard, the stimulating f/x of GHB are more prevalent at lower doses (less than the typical 2-3g) due to the relatively low affinity for GABAb vs GHBr. Or you may even try combining it with e.g. caffeine or another, (even amphetamine-type) stimulant as long as you don't overdo it.
Racetams do indeed potentiate stimulants, I believe that it has something to do with increased activity at certain metabotropic glutamate receptors (of which racetams likely modulate & amphetamine derivatives interact with). Do note that NMDA/AMPA are ionotropic & not metabotropic so this would still be a 2nd order effect.
On the topic of ibogaine & DXM, they are both pretty broad-spectrum drugs and are much more than a "pure" NMDA antagonist. I know Ibogaine at least is a SNDRI (S>D>N in terms of potency) plus opioid agonist (mu and kappa) and also interacts with 5-HT receptors. It's not very potent but people take it in multi gram boluses so I would expect a real fireworks show. DXM is "only" a SNRI (N>S) but has all this funky rate-order mechanics shit with the conversion to DXO (which is more potent as a NMDArA, and from what I can tell seems more like a version of ketamine with activity at SERT). In addition both drugs are calcium channel/nicotinic blockers (as is ketamine/MXE/memantine). There is also sigma-1 and 2 agonism to consider as well... truly rhese drugs that are thought of as NMDA antagonists may be working through other modes of action.
I wonder how much of it is all psychological, though, from people simply becoming 'entrained' to drug use... like riding the same roller coaster every day, if you will. You can ride that coaster every day until you no longer find pleasure in it, and when that point is reached you can definitely come back after months or years of being in a different mind state & recapture that thrill. Of course it will never be quite as exciting as the first time because some of the novelty has gone, but it likely won't be 'boring' as it were if you were riding it daily for 3 weeks. Continuing to ride the coaster over and over when you don't like the experience should be reserved for roller-coaster test pilots & sadomasochists. I'm not denying that some drugs develop a physical tolerance, but in some cases I bet it's just a case of your 'escape of choice' becomign boring.
Re: risperidone for ... well, anything but major delerium & schizophrenia - wtf? I do not understand why this industrial strength antidopaminergic is prescribed as frequently as it is. From whatI have read it seemms incredibly effective at makiing you not care about a single fucking thing, be unwilling/unable to think, and possibly inducing black, death-like sleep and/or motion dyskinesias/tics. I can't remember reading anything that suggest widespread blockade of the dopamine/5ht systems is good for any sort of drug dependence. Maybe for an out of control acid trip, or a schizophrenic meltdown, or sedating someone as a last-resort, but not GHB dependence.
MXE has a stronger affinity as a DRI and is blocking the amphetamines.
On trhe topic of MXE, I think it's a damn strong DRI & definitely not an "anti-addictive" agent any more than PCP/ketamine is. (Probably due to this property,) I have also seen it precipitate quite the washout similar to cocaine when overused or used in naive individuals (probably in combination with stimulants)... consisting mainly of inattention, head fog, & sleepiness. 6-24h after last dosing Relieve it with a solid dose of caffeine if you have to work.