This is especially true when the cognitive deficits are subtle or absent at the time that the patient is first evaluated. Another complication is the presence of delirium in chronic psychotic patients. Due to the prevalence of substance abuse, as well as the strong anticholinergic and other toxic effects of psychotropics, delirium is often overlooked in the psychiatric population. It is rare for patients to present with all the classic symptoms. Usually, the disorder develops over hours or days, but the unaccompanied patient may not be able to provide this time course.
Confusion can be very subtle and inconsistent.
There may be irritability, sleepiness, agitation, paranoia, and sundowning. Mood can shift rapidly. Speech may be illogical or well-organized. Hallucinations and delusions are common. One should automatically suspect delirium in the presence of visual, olfactory, or tactile hallucinations.