Mental health problems have been reported as one of the principal causes of incapacity and morbidity. According to the World Health Organization approximately 15% of adults aged 60+ and over suffer from a mental disorder. In the oldest old population, a higher deterioration in the mental state is expected, which is ought to increase the risk of incidence of mental problems and use of healthcare services. The aim of this study is to examine inpatient episodes with a mental disorder coded as primary discharge diagnosis between 2000 and 2014 by patients aged 80+ in Portugal mainland.

Exploratory descriptive analyses of data regarding the number of episodes and coded diagnosis on admission were performed.

From a total of 1,837,613 inpatient episodes, 16,430 (0.9%) correspond to episodes having a psychiatric disorder as a primary discharge diagnosis. Delirium, dementia and amnestic and other cognitive disorders (60.1%), alcohol-related disorders (17.7%) and mood disorders (8.6%) were the most common diagnosis. An analysis by age group revealed that among octogenarians and nonagenarians delirium, dementia, and amnestic and other cognitive disorders were the most common diagnosis; in the centenarian group; however, these were outweighed by alcohol-related disorders.

Findings from this study document the importance of neurocognitive disorders as a primary reason for hospitalization in the oldest old, but also highlights the need of paying attention to other mental disorders among this age group. Further studies should examine the prevalence of medical comorbidities in patients with mental disorders.