Having seen a few shows over the years, I've always been impressed by how they test out songs and ideas live before they get released. Some songs (Dora Peach -> Ratcatcher, Close Your Eyes ++) were played for years before finally finding their version on a record. Sometimes the final song version has changed a lot from start to finished song. MP have always been ahead of everything regarding releases. Most other bands play old songs on repeat….
They're surely no strangers to pot and shrooms for leisure, maybe some jamming and reaching for ideas thrown in, but eventually you can't write and perform this music when you're high. They're hard working pros and musically driven and totally focused. As easy as that. Drugs are way overrated when it comes to creativity.
That said I've been seriously baked when I've heard Motorpsycho the first time ever (and it was the full Demon Box album) and it was also the last time ever. Who needs drugs if you got Motorpsycho?