Not the case for me. GHB has to me a more refined and quasi-trippy and ecstatic buzz to it than alcohol's blunt queasiness. Similar in some aspects but really a pretty different feel if dosed properly. It significantly modified the mushroom experience into one that was even more physically and mentally ecstatic to the point that it felt I was physically on another vibrational plane of reality. I know shrooms on their own can allow that and almost anything else imaginable to happen in the mind, but it just felt qualitatively deeper and smoother and somehow more "organized" (words fail of course) with the ghb... There was definitely a noticeable and very pleasurable, physically and mentally sensual, synergism. I did the combination a number of times and considered it a surefire shroom anxiety blocker and ecstatic "sensation of flying" promoter. BUT that may just be me, it also seemed rather volatile and fragile, like someone with a slightly different metabolism or disposition could have quite different results, so care is of course needed.