Back to your topic GWB, I myself have been consuming SC thinking these were normal, natural cannabinoïds in the form of hash for 2 years, daily, in a junky-like fashion, from my 15th to my 17th approx. I quitted everything (SCs, alcohol, benzos and Speed/X) after a heavy binge-drinking, speeded-up and smoked up summer; all at once. This sudden deprivation of self-medication precipitated schizophrenic like symptoms and a heavy-duty psychosis, along with lethargy, anxiety, depression and irritability. I ended up losing contact with +150 peeps I used to hang out with. These symptoms lasted for about 6 months, and I had to be hospitalized in a specialized departement of neuro-psychiatry. All in all, I'm telling you this because they (the group of 6 highly competent neuroscientifics and psychiatrics etc) concluded that the SCs that I used daily had caused a gigantic desensibilisation at my endocannabinoïd receptors (the CB1 and CB2, plus some other ones in your belly, muscles and all the nerve tissues in your body) that are known to regulate (along with a lot of other stuff) dopaminergic (+norepinephrine, the "stress" molecule), serotonergic and GABAergic function in your body, but also immune system functions, hormonal functions and a lot of other vital stuff. This de-sensibilisation had led to a state of "no-control" of my body over these mecanisms, as the natural endocannabinoïds my body was throwing out weren't "strong" enough to behave as agonists at these receptors. To make it short:
SCs fuck up the way your endocannabinoïds affect your body, turning it into a unresponsive son of a bitch to what it normally should be working with. Why? Because as you said, SCs are "full agonists" and at some receptors, even "irreversible" (look it up).
More than 18 months later, and having researched the subject like no other motherfucker could have, I can tell you that the best way to go would be to "train" your CB receptors to function normally again. Keep in mind that they take part in the regulation of almost everything in your body, from hunger to sleep, immune-system to bowel function, etc. You can do that by starting to withdraw in a very simple way: You lower the dose you consume /day and the time in between each dosing by a 5% every day. Keep doing so until you consume 1/10 of the minimal active dosage (in the 1/10 of a mcg for ADB-FUBINACA, e.g); eventhough you don't think that it affects you (you won't feel a high with such small dosages), it has been proven that microdosing does help lowering withdrawal effects and that it helps re-establishing the responsivity of your receptors (they "seek" activity from compounds; if you went from x10000 in power to x1, it's normal they don't "find" the activity, but if you go from x10000 to x9990 to x9980 etc, they'll stay "responsive" in a fashion that permits you to slowly quit).
I myself understood this much later, with the help of psychiatrists, a biologist and a lot of introspection and research.
My dopaminergic system is fucked-up (not unlike parkinson patients) in a way that I have to be treated with ADHD medication to function normally (my cognitive, memory and pleasure systems have lost more than 1/2 their "normal" potency, compared to baseline people), but that I could only start months after my last psychotic and anxiety symptoms flushed away, for security reasons. (ADHD treatments can worsen anxiety and social withdrawal).
If your willing to stop, tell yourself that the worst is only just starting, and that it's gonna take at least 6 months of your life to "function" normally again, be it sleep, cognition, beeing able to have fun , or just not craving that stuff any longer, w/out taking in account the long weeks you'll have to go through to slowly reduce the consumed amounts in order to re-establish a as good a possible functionning receptor system.
EDIT: If you can, and have the money it'll take, try doing this "reducing daily consumed dosage" thing with natural weed, and not dronabinol, which might just be worse than some SCs out there (precipitates schizophrenia even faster in predisposed patients).
LaGaf