Psychosis in Elderly Patients: Causes and Diagnostic Approach

Introduction to Psychotic Symptoms

Delirium is the most common cause of psychotic symptoms in elderly patients presenting to emergency departments, characterized by inattention, fluctuating consciousness, and acute onset over hours to days, with infection being a common precipitating factor 1, 2, 3
Critical distinction: Unlike primary psychosis, delirium involves altered consciousness and disorientation, whereas psychosis typically maintains intact awareness and level of consciousness 1, 2, 4

Secondary medical causes that directly produce psychotic symptoms include endocrine disorders, autoimmune diseases, neoplasms, neurologic disorders, infections, metabolic disorders, and nutritional deficiencies 1, 2, 5

Drug-related psychosis occurs through multiple mechanisms, including intoxication, withdrawal states, and side effects or toxicity from prescribed medications 1, 2, 5

Evaluate for fluctuating consciousness, disorientation, and inattention (delirium) versus intact awareness (psychosis) 1, 2, 5
Missing this distinction is a critical pitfall that doubles mortality 1, 2

The American College of Radiology recommends a systematic approach to rule out secondary causes, including reviewing medications, evaluating for underlying medical conditions, and considering neuroimaging 1, 2, 5
The diagnostic criteria for dementia-related psychosis have been revised, representing a distinct clinical entity 1, 2, 4
Depression with psychotic features must be distinguished from other etiologies 1, 2, 4

Don't overlook withdrawal states, which require immediate benzodiazepine treatment to prevent seizures 5
Don't delay neuroimaging when focal neurological signs, head trauma history, or atypical features are present 5

Central nervous system infections, such as encephalitis or meningitis, typically present with fever and altered mental status, and may cause psychotic symptoms, particularly in elderly patients 6
Traumatic brain injury should be considered with recent head trauma history, and may present with psychotic symptoms 6
Stroke or cerebrovascular disease may present with psychotic symptoms, particularly in elderly patients 6
Brain tumors, such as oligodendroglioma, glioblastoma, or meningioma, can present with primarily psychiatric symptoms, including psychosis, though this is rare 7
Seizure disorders, including nonconvulsive status epilepticus and postictal states, can cause psychotic symptoms 6
Inflammatory disorders, including autoimmune encephalitis, can present with psychotic symptoms 6

Systemic infections with sepsis can precipitate delirium with psychotic features 7

The American College of Emergency Physicians states that routine laboratory testing need not be performed when patients are clinically stable, but may be necessary for patients with concerning findings on history or physical examination, or new-onset or acute changes in psychiatric symptoms 7
Neuroimaging with CT or MRI is usually appropriate if clinical suspicion for acute neurological cause is high, or if symptoms do not respond to management, according to the Journal of the American College of Radiology 6
Neuroimaging is indicated for patients with focal neurological deficits, head trauma history, atypical features, new-onset psychosis in elderly patients, or first episode psychosis with neurological signs 6

In children and adolescents, peer or romantic conflicts may be precipitants of psychotic symptoms, and bipolar disorder with psychotic features is frequently misdiagnosed as schizophrenia 7