Both can present with hallucinations, delusions, or disorganized thinking tied to a medical condition, but delirium is defined by an acute disturbance of attention and awareness with a fluctuating course, while psychotic disorder due to another medical condition presents with prominent hallucinations or delusions without the core attentional/awareness disturbance of delirium.
Delirium typically develops acutely over hours to days and fluctuates markedly; psychotic disorder due to another medical condition can have a more stable, sustained presentation tied to the underlying illness.
Delirium is often reversible once the underlying acute cause is treated and tends to resolve relatively quickly; psychotic disorder due to another medical condition persists as long as the underlying medical condition remains active.
Delirium features prominent disturbances in attention, awareness, and cognition that wax and wane, often worse at night; psychotic disorder due to another medical condition does not center on this fluctuating attentional disturbance.
Both can be medically urgent, but delirium in particular signals an acute medical emergency requiring immediate workup.
If disturbed attention, awareness, and a fluctuating course are present, delirium takes diagnostic precedence over psychotic disorder due to another medical condition.
Assessing attention and level of consciousness, and tracking whether symptoms fluctuate over the course of a day, is the key step separating the two.
Prominent hallucinations in a medically ill patient can be labeled as a psychotic disorder before the fluctuating attentional disturbance characteristic of delirium is recognized.
A hospitalized patient who is lucid in the morning, confused and hallucinating by evening, with poor attention throughout, points to delirium rather than a stable psychotic disorder due to a medical condition.
| Feature | Psychotic Disorder Due to Another Medical Condition | Delirium |
|---|---|---|
| Attention/awareness | Not centrally disturbed | Core disturbance, fluctuating |
| Course | Relatively stable, tracks illness | Acute onset, fluctuates markedly (often worse at night) |
| Urgency | Warrants medical workup | Medical emergency requiring immediate evaluation |
Prominent hallucinations or delusions judged, based on history, physical examination, or laboratory findings, to be the direct pathophysiological consequence of another medical condition, not occurring exclusively during delirium.
An acute, fluctuating disturbance in attention and awareness, developing over a short period, with an additional cognitive disturbance, that is a direct physiological consequence of an underlying medical condition, substance, or other cause.