The remedy to GMS is sheer bloody minded determination. Typically it strikes when in the middle of act two during the first draft of any given novel. Up until then, the writing process has been undertaken in a halcyon delusion that I'm writing the greatest novel ever written.
GMS then strikes with furious vengeance, and lingers thereafter until I finish the draft, by which point I'm convinced I've written the worst novel ever, and I promptly shelve it for six months. After that, I reluctantly read it again, and realise it's actually not that bad, and with a bit of spit and polish it could be presented to the great unwashed. But it isn't the greatest novel ever written.
Alas, this is a cyclical process. I can't not write, otherwise the voices in my head demanding to be put on paper don't shut up. But GMS always lurks in wait, ready to twist the knife. I've got used to it now.
So no, there isn't a booze related remedy. But a trip to the bar is always a good idea in any case.