Delirium is an acute disorder of attention and cognition with a fluctuating course caused by physiological abnormalities. The syndrome is common, serious, under-recognised, and can be fatal.

There are very few studies concerning mortality of delirious patients in psychiatric departments, just as there is a lack of literature on delirium in psychiatric patients in general.

To determine the psychiatric co-morbidity profile of Danish psychiatric inpatients diagnosed with delirium, and to analyse the standardized mortality rate ratio and predictors of mortality in the same patients from 1995 through 2012.

All first time-ever diagnoses of delirium among psychiatric inpatients were identified in the nationwide Danish Psychiatric Central Research Register (DPCRR) from 1995 through 2012. The delirium diagnoses include 1) delirium unspecified, 2) delirium in dementia, and 3) delirium drugrelated, all in accordance with ICD-10. The mortality rates were age-standardized and the statistical analyses performed with STATA 12.

A total of 7,246 persons diagnosed with delirium was identified in the DPCRR between 1995 and 2012.

Dementia was present in 7% before a diagnosis of unspecified delirium, and about one sixth was diagnosed with dementia after the episode of delirium. A dementia-diagnose before, co-occurring, and after delirium in dementia was seen in 39.8%, 61.9%, and 54.5% respectively.

Drug-related delirium co-occurred most often with another substance-use related disorder. Sedatives or hypnotics cover the majority of substance use at the time of drug-related delirium.

Further analyses are presently in progress.

In progress.