The story behind
Pink Floyd wrote Brain Damage in 1973, as part of the album The Dark Side of the Moon. The song was recorded at Abbey Road studios, and at one point used an arpeggio from Dear Prudence by the Beatles, something that did not cause any copyright issues, as it is supposed there was a friendly agreement.
Roger Waters wrote it during the Meddle tour, along with Money, and originally it was called The Dark Side Of The Moon, a name that eventually became the album's title. The song was dedicated to Syd Barrett, whose mental health had deteriorated due to drug use.
At first it was going to be sung by David Gilmour, but in the end it was Waters who did, while Gilm made the choruses. The laughter at the end is from Peter Watts, who also can be heard saying some phrases between songs. The song lasts 3:52 and is mixed with Eclipse at the end, as if it were a single piece.