Background: Although suicide rates among prisoners are high and vary between countries, it is uncertain whether this reflects the importation of risk from the general population or is associated with incarceration rates.
Methods: We collected data on suicides and undetermined deaths in 12 countries (Australia, Belgium, Canada, Denmark, England and Wales, Finland, Ireland, Netherlands, New Zealand, Norway, Scotland, and Sweden) directly from their prison administrations for 2003-2007. These were compared with rates of suicides in the general population separately by gender using Pearson's correlations. In addition, they were compared with rates of incarceration. Linear regression was used to examine any association after adjustment for rates of incarceration.
Results: Data were collected on 861 suicides in prison, of which 810 were in men. In the men, crude relative rates of suicide were at least three times higher than the general population. Western European countries had similar rates of prisoner suicide which were mostly higher than those in Australia, Canada, and New Zealand. There was no association between rates of suicide in prisoners and general population rates or rates of incarceration. In the women, inmate suicide rates varied widely and were mostly raised compared with rates in the general population. In addition, these rates did not appear to be associated with general population rates of suicide.
Conclusions: Rates of prison suicide do not reflect general population suicide rates, suggesting that variations in prison suicide rates reflect differences in criminal justice systems including, possibly, the provision of psychiatric care in prison.