[hutzlibu]

Sounds like "Das weiße Rauschen"? (The white noise, but I think he did mushrooms)

If so, I saw that one too ...

[Leparamour]

That's the one and you're right, according to wikipedia they were doing magic mushrooms not LSD.

Great and intense movie. So far the only time where I can say with certainty that a movie changed my life.