This paper in Lancet Psychiatry ,Vol 3 ,June 2016 examines the question : what role do health services have in suicide prevention ? The research is part of the National Confidential Inquiry into Suicide and Homicide by People with Mental Illness ( NCISH) for individuals aged 10 years and older who died by suicide in England between Jan 1 1997 and Dec 31 2012 , and who had had at least one contact with mental health service within 12 months of death ( referenced in previous post 20 )
To calculate rates of suicide, they used the denominator data for the number of people in contact with mental health services . Rates were expressed per 10,000 contacts with mental health services by per year .
They compared suicide rates before and after implementation of 16 key recommendations and service changes designed to improve safety within 62 National Health Service ( NHS) geographical mental health services
The five recommendations associated with the biggest decrease in suicide were four policy changes plus creation of intensive home treatment teams ( called crisis resolution and home treatment teams in England – CRHT )
Differences in suicide rates before and after implementation were calculated as Incident Rate Ratios ( IRR) . For intensive home treatment ( CHRT) teams the IRR was 0.73 i.e. a 27 % reduction in the suicide rate .
The study was observations therefore causal inferences could not be made
Ironically, this research is by the same group mentioned in post 20 who had made what I regarded as unwarranted inferences regarding the safety of intensive home teams regarding suicide risk
mental health service changes and patient suicide