from some website i found:
"1972
Paul and Linda McCartney are busted for smuggling hashish into Sweden. He pays a $2,000 fine.
1973
McCartney is busted for growing marijuana on his farm in Scotland. He is fined the equivalent of $240.
McCartney visits John Lennon and Harry Nilsson, who are living together in L.A. while Lennon produces Nilsson's album, "Pussy Cats." A bleary-eyed Nilsson offers McCartney some PCP. Paul asks, "Is it fun?" "No," Nilsson replied. So McCartney passes on the PCP.
1974
According to a book written by May Pang called Loving John: The Untold Story.. about the time she spent as John Lennon's girlfriend, John Lennon and Paul McCartney drop acid together one day in New York City in 1974 and decide to go visit David Bowie.
Bowie has just received the final mix of his latest album, Young Americans.. which includes two songs that John Lennon worked on. One was a reworking of The Beatles song, "Across the Universe," and the other was to become Bowie's first number one hit, "Fame," co-written with Lennon. Bowie proudly plays the new album for his two Beatles heroes and they're impressed. And so he plays it again. And again. And again. Eventually, McCartney excuses himself and bolts out the door, Lennon following quickly behind.
1975
Linda McCartney is busted for possession of marijuana in Los Angeles, but charges are dropped.
January 16, 1980
McCartney famously busted in Japan at the start of a planned tour with Wings with approximately half-a-pound of marijuana in his suitcase. He spends ten days in prison in Japan before being released and deported. After his release, he promises to quit but also argues that it is less harmful than Valium or alcohol. He also later comments that he just couldn't leave the pot behind because "it was such good stuff."
1984
Paul and Linda McCartney busted in Barbados for possession of marijuana. Several days later, Linda is busted again flying into Heathrow Airport in London with marijuana.
In college in the late 1970s, I had a girlfriend from The Hamptons who had been the baby sitter for Paul and Linda McCartney. (Paul and Linda and their children lived in that elegant Long Island suburb through most of the 1970s). Lizzie hated babysitting for the McCartneys because they were slobs (messy house) and because there were "drugs all over the place," right out in the open where theoretically one or all of their four young children could get at them. When I questioned Liz more closely about the drugs, she mentioned white powders, mushrooms and (no surprise) marijuana."