Impact on in-patient stays / re-admission rates of including systemic family/couple work in treatment plan??

I'm hunting around for any research (formal/informal, published/unpublished)
on any impact on in-patient stays (or 'bed days') or re-admission rates to
in-patient settings when systemic family or couple work is included as part
of a treatment plan?

Any leads would be very helpful. Thanks very much,

Maeve Malley
Maeve.Malley@oxleas.nhs.uk