SUMMARYThis article reports a survey by the Team for the Assessment of Psychiatric Services (TAPS)* of all inpatients aged 70 years or more resident in Claybury Hospital, London, for more than 12 months. Age, sex, total length of inpatient stay and type of care received were recorded for each subject. and assessments using the Mini-Mental State Examination (MMSE) and Modified Crighton Royal Behavioural Rating Scale (MCRBRS) were performed. Of 189 inpatients who completed the assessments, 142 (75%) showed unequivocal, severe cognitive disability (MMSE < 17). Patients were assigned to 'functional', 'organic' or 'mixed' diagnosis groups by staff report and case note review. A staff report of 'mixed' diagnosis missed a large number of patients who had an original diagnosis of functional psychiatric disorder plus severe measured cognitive disability. Sixty-five per cent of patients with an original diagnosis of functional psychiatric disorder fell into this category. AFter controlling for age, sex and total length of inpatient stay, patients with a severe degree of reported behavioural problems (MCRBRS 2 17) were almost 23 times (95% CI 6.6-79.4) more likely to receive specialized psychogeriatric care than other patients. Severe cognitive disability was not associated with type of care received. Issues related to measurement of cognitive disability across disparate diagnostic groups are discussed. KEY woRDs4lderly mentally ill; dementia; schizophrenia; comorbidity; cognitive disability; behavioural disability Despite government policy supporting the closure of psychiatric hospitals, little is known about the disabilities of long-stay elderly mentally ill (EMI) inpatients and the alternative services necessary to provide for their care in the community. Suggestions for optimal care are available (Blessed, 1988;Murphy, 1992) and some innovative pilot projects report beneficial outcomes upon resettlement (Dean et al