Patients in the intensive care unit (ICU) often suffer from medical illnesses with psychiatric manifestations, or from life-threatening reactions to psychotropic drugs. Psychiatrists are frequently consulted to assist in sorting out diagnostic conundrums and crafting treatment regimens that address not only the presenting symptoms, but also the underlying causes. In a recent article titled “Treatment of Four Psychiatric Emergencies in the Intensive Care Unit,” authors Jonathan E. Seveansky, O. Joseph Bienvenu, Karin J. Neufeld, and Dale M. Needham discuss four of the most common emergencies that present in the ICU setting — agitated delirium, neuroleptic malignant syndrome, serotonin syndrome, and psychiatric medication overdose.1

According to the authors, patients with delirium experience “a disturbance of consciousness” with a “reduced ability to focus, sustain, or shift attention, along with a change in cognition (e.g., memory deficit, disorientation, or language disturbance) or a perceptual disturbance (e.g., visual hallucinations) not better accounted for by dementia.”

There is considerable overlap between these symptoms of delirium and similar symptoms associated with other psychiatric conditions. To assess these symptoms, the authors recommend using screening instruments that are specifically validated for the ICU setting. These include the Confusion Assessment Method for the ICU (CAT-ICU)2, the Intensive Care Delirium Screening Checklist (ICDSC)3, and the Richmond Agitation-Sedation Scale (RASS).4

Because the etiology of delirium is often multifactorial, the authors suggest a mnemonic, “I WATCH DEATH,” as a helpful approach to thinking systematically about risk factors:

Risk Factor



Central nervous system, systemic


Alcohol, sedatives

Acute metabolic

Electrolyte or acid-base imbalance, liver/kidney failure


Brain injury, surgery, heat stroke, hypothermia, severe burns

Central nervous system pathology

Tumor, hematoma, hydrocephalus, epileptic seizure, vasculitis, hydrocephalus


Respiratory failure, left heart failure, hypotension, carbon monoxide poisoning


Vitamin deficiency


Cortisol or glucose dysregulation, hypothyroidism, hyperparathyroidism

Acute vascular

Cerebrovascular accident, shock, arrhythmia, hypertensive encephalopathy


Pesticides, solvents, alcohol/illicit drugs, anticholinergics or g-aminubutyric acid-ergic agents

Heavy metals

Lead, manganese, mercury

Additional risk factors include immobilization, urinary/fecal retention, and sleep deprivation.