To examine factors associated with the number of psychiatric admissions per in-patient suicide and the suicide rate per 100 000 in-patient years in psychiatric hospitals.
Random-effects meta-analysis was used to calculate pooled estimates, and meta-regression was used to examine between-sample heterogeneity.
Forty-four studies published between 1945 and 2013 reported a total of 7552 in-patient suicides. The pooled estimate of the number of admissions per suicide calculated using 39 studies reporting 150 independent samples was 676 (95% CI: 604–755). Recent studies tended to report higher numbers of admissions per suicide than earlier studies. The pooled estimate of suicide rates per 100 000 in-patient years calculated using 27 studies reporting 95 independent samples was 147 (95% CI: 138–156). Rates of suicide per 100 000 in-patient years tended to be higher in more recent samples, in samples from regions with a higher whole of population suicide rate, in samples from settings with a shorter average length of hospital stay and in studies using coronial records to define suicide.
Rates of in-patient suicide in psychiatric hospitals vary remarkably and are disturbingly high. Further research might clarify the extent to which patient factors and the characteristics of in-patient facilities contribute to the unacceptable mortality in psychiatric hospitals.