The effect of a hospital liaison psychiatry service on inpatient lengths of stay: interrupted time series analysis using routinely collected NHS hospital episode statistics.

Using routine NHS data for a whole hospital it was not possible to replicate a previous report that a rapid access liaison psychiatry service for inpatients produces substantial reductions in length of stay, and commissioners of services should be cautious of claims to the contrary. Further research to determine if there is an effect for sub-groups will require major improvements in the way co-morbid mental disorders are coded in NHS practice.