Age-matched patients attending a geriatric psychiatry day hospital, one group with Alzheimer’s dementia and another with functional illness, were studied and compared with similar inpatient groups. Erythrocyte ouabain binding was assayed and Clifton ratings completed. In day hospital patients ouabain binding was significantly lower in the demented group (p < 0.008) than in the functional group. There was a positive correlation between Clifton ratings and ouabain in the whole group (p < 0.05). No significant differences were found in inpatient groups. Possible reasons for findings are discusse