Delirium: patient characteristics that predict a missed diagnosis at psychiatric consultation.

Objective: This study evaluates patient characteristics that might predict a missed diagnosis of delirium prior to being seen by a psychiatric consultant.

Method: Study participants were assessed using quantitative standardized scales of cognitive function, delirium and physical impairment.

Results: Referring service personnel missed the diagnosis of delirium in 46% of psychiatric consultations. Two factors were associated with their failure to identify delirium accurately: use of a past psychiatric diagnosis to explain delirium symptoms and the presence of pain. Symptoms of delirium and quantitative scale scores did not distinguish between patients with whom diagnosis had been missed and those with accurate diagnoses.

Conclusion: The consulting physicians of patients with delirium often incorrectly turn to past psychiatric diagnoses and/or are distracted by the presence of pain and, thus, fail to accurately diagnose delirium.