About 9 million people are imprisoned worldwide, but the number with serious mental disorderspsychosis, major depression, and antisocial personality disorderis unknown. Seena Fazel from the University of Oxford and John Danesh from the University of Cambridge, UK, did a systematic review of surveys on such disorders in general prison populations in 12 western countries.
62 surveys included 22,790 prisoners (average age 29 years, 81% men). Around a quarter of prisoners were violent offenders in the 27 surveys with appropriate data. About 4% of men had psychotic illnesses, 10% major depression, and 65% a personality disorder, including 47% with antisocial personality disorder. 4% of women had psychotic illnesses, 12% major depression, and 42% a personality disorder, including 21% with antisocial personality disorder. Prisoners were two to four times more likely to have psychosis and major depression, and about ten times more likely to have antisocial personality disorder, than the general population.
Seena Fazel comments: "Since a few million prisoners worldwide probably have serious mental disorders (including several hundreds of thousands with potentially treatable psychosis or depression), the ability of prison health services in some countries to address these problems may well require review."