But What About "Knocked Up's" Psychedelic Plausibility?

As the moviegoing public quite understandably debates the real-world probability of someone like Katherine Heigl hooking up with someone like Seth Rogen, this ol' Florida boy would like to point out that there's another, 'til now unremarked upon, "Knocked Up" accuracy issue.
In the sequence where Rogen and his virtual brother-in-law Paul Rudd ditch their ladies for a guys' getaway in Vegas, the men get all paranoid and hyper self-conscious after consuming magic mushrooms. Now, it's been many, many years since I left the Sunshine State - where, in case you didn't know, the atmosphere is perfect for generarting psilocybin spores - and I'm not copping to anything that could be used against me. But I recall being informed, on impeccable authority, that mushrooms were always the most mellow, angst-free hallucinogens, naturally untainted by the freakout-inducing chemicals found in synthetic pharmaceuticals like LSD and mescaline.
Of course, any visit to Vegas these days could make a sensible person flip. But this sequence just makes me wonder if writer-director Judd Apatow knows anything more about recreational drugs than he does about the female mind.