Readmission to psychiatric units of acute care hospitals
Healthc Q. 2007;10(2):30-2.
Madi N, Zhao H, Li JF.  Hospital readmissions for patients with mental illness in Canada.
In Canada, during the years 2002-2004, 37% of patients discharged with a mental illness diagnosis were readmitted at acute care hospitals within a one year period.

Readmission to psychiatric hospitals
Psychol Rep. 2003 Dec;93(3 Pt 1):816-8.
Feigon S, Hays JR.  Prediction of readmission of psychiatric inpatients.
Prospective study of 943 patients admitted to an urban psychiatric hospital.  Over 5 years of follow up, 33% of the patients (all ages) had at least one readmission.

Aust N Z J Psychiatry. 2011 Jul;45(7):578-85.
Zhang J, et al.  Factors associated with length of stay and the risk of readmission in an acute psychiatric inpatient facility: a retrospective study.
Retrospective study of 286 randomly selected admissions over 12 month period.  Of the 178 patients involved in these admissions, 46% were readmitted during this 12 month period.

Readmission to geriatric psychiatry inpatient unit
J Geriatr Psychiatry Neurol. 2006 Dec;19(4):226-30.
Woo BK, et al.  Factors associated with frequent admissions to an acute geriatric psychiatric inpatient unit.
Study included 424 consecutive admissions to a university-based geriatric psychiatry inpatient unit over a 20-month period. Mean age of patients was 79.4 years.  35.6% were readmissions.