The new version of DSM-5 provides nearly the same criteria as DSM-IV for delirium with an exception. The DSM-5 requires a disturbance in awareness while DSM-IV, a disturbance in consciousness.

Awareness is not the same as consciousness. In this study we examined the concordances between awareness and consciousness and the agreement between DSM-5 and DSM-IV.

All acute medical admissions 70 years and over. Exclusion criteria: terminal phase of illness, severe aphasia, intubated. Those included were assessed on Day 1, 3, 7, 10 of their admission. During the assessment each individual was tested with: MoCA, DRS-98R, CAM, RASS and the subscale of levels of consciousness and awareness of surroundings from RCDS; APACHE II, CAPE and BARTHEL index. Demographic data and a medication list were also recorded.

123 participants;

Mean age: 81.3 SD (6.7) range 70-100 years old

Females 60(48.9%)

Delirium according CAM 21 (17.1%)

Delirium 23 (18.7%)

Subsyndromal delirium 28 (22.8%)

No delirium 72 (58.5%)

Previous cognitive decline: 76 (61.8%)

RCDS (awareness and consciousness)

Mean awareness: 0.4, SD (0.8)

Mean consciousness 0.4 SD (0.8).

Correlation (agreement) between awareness and consciousness Kendal's Tau =260, p=0.026

Using the awareness definition of delirium 8 participants with full awareness of surroundings have been indentified as delirious according to DRS 98, while using the consciousness definition 12 participants where indentify as delirious.

DSM-IV and DSM-5 detect two slightly distinct populations with delirium. Awareness and consciousness are not the same. DSM-5 is more restrictive in indentifying delirium.