He became bored with the guitar and sought exotic instruments to play, and he was increasingly absent from recording sessions. In Peter Whitehead's promotional film for We Love You, made in July 1967, he appears extremely groggy and disoriented.
Jones was arrested for drug possession on 10 May 1967, shortly after the "Redlands" incident at Richards' Sussex home. Authorities found marijuana, cocaine, and methamphetamine in his flat. He confessed to marijuana use, but claimed he did not use hard drugs.
In June 1967, he attended the Monterey Pop Festival. There he met Frank Zappa and Dennis Hopper, and went on stage to introduce the Jimi Hendrix Experience who were not yet well known in the United States.
Hostility grew between Jones, Jagger, and Richards, alienating Jones further from the group. Although many noted that Jones could be friendly and outgoing, Wyman, Richards, and Watts have commented that he could also be cruel and difficult. By most accounts, Jones' attitude changed frequently; he was one minute caring and generous, the next making an effort to anger everyone. As Wyman observed in Stone Alone: "There were at least two sides to Brian's personality. One Brian was introverted, shy, sensitive, deep-thinking. The other was a preening peacock, gregarious, artistic, desperately needing assurance from his peers." "He pushed every friendship to the limit and way beyond".
Jones' last substantial sessions with the Stones occurred in spring and summer of 1968, when the Stones produced "Jumpin' Jack Flash" and the Beggars Banquet album. He can be seen in the Jean-Luc Godard film One Plus One playing acoustic guitar and chatting and sharing cigarettes with Richards, although Jones is neglected in the music-making. The film chronicles the making of "Sympathy for the Devil".