Known for his perfectionism and for being highly self-critical, even in victory, he has suffered from depression and struggled with drug addiction and alcoholism in his early career. Psychiatrist Steve Peters, a close friend, has been helping him overcome his mood swings since 2011. He is also a close friend of artist Damien Hirst. Noted for repeatedly declaring his intention to retire, O'Sullivan took an extended break from the professional snooker tour during the 2012–13 season, during which he worked on a pig farm for several weeks. He enjoys running, and has achieved a personal best of 34 minutes and 54 seconds for 10 km races, which ranked him in the top 1,500 10k runners in the UK in 2008. He enjoys cooking, and appeared on the BBC's "Saturday Kitchen" in December 2014 and February 2021. He also enjoys motor racing, and has appeared on "Top Gear". He is a supporter of Arsenal FC.