Background: Mental capacity has been little studied among older general hospital inpatients.

Methods: A retrospective analysis was undertaken of routinely collected data (age, gender, ethnicity, admission diagnosis, psychiatric diagnosis, Mini-mental State Examination score, whether capacity was assessed, the outcome of that assessment, and discharge destination) on referrals to a liaison psychiatry service for older people (2003–2006) from medical and surgical teams at a large London teaching hospital.

Results: 1267 patients were referred to the service, of whom 379 (30%) were assessed for capacity. The most common mental capacity issues were placement (303 assessed of whom 54% lacked capacity), treatment (86 assessed, 59% lacking capacity) and finances (70 assessed, 79% lacking capacity). Cognitive impairment, dementia and delirium, rather than mental disorders were associated with incapacity. Those assessed and deemed to lack capacity for placement decisions were twice as likely to be placed in a care home, and four times as likely to be placed in an elderly mentally ill (EMI) facility, independent of dementia diagnosis and cognitive functioning.

Conclusion: Referrals to a liaison psychiatry service for older people for assessment of mental capacity are common. The main mental capacity issues in older people were those linked to discharge planning. The relatively high proportion of those found to have capacity when capacity had been queried by referring clinicians attests to the important role of specialist liaison teams, particularly in complex cases, in protecting the autonomy of vulnerable older people, and avoiding institutionalization.