What is the recommended medical workup for psychosis?

Medical Workup for Psychosis

A thorough physical examination and targeted laboratory testing should be performed to rule out medical causes of psychosis, with neuroimaging reserved for patients with atypical presentations, abnormal neurological findings, or focal deficits. 1

Initial Clinical Assessment

History and Mental Status Examination

• Obtain detailed evaluation of psychotic symptoms including delusions, hallucinations, disorganized speech/thought, abnormal motor behavior, and negative symptoms 1, 2
• Document symptom onset, course of illness, and any prodromal features such as social withdrawal, declining academic/occupational performance, or deteriorating self-care 1, 3
• Assess for comorbid conditions including mood disorders, substance abuse, developmental delays, and family psychiatric history with focus on psychotic illnesses 1, 4
• Obtain collateral history from family members to establish presentation timeline and functional decline 3, 4
• Evaluate for risk factors including recent head trauma, seizures, cerebrovascular disease, new headaches, or subacute onset suggesting oncologic cause 4

Physical and Neurological Examination

• Perform complete physical examination with attention to vital signs: tachycardia or severe hypertension suggests drug toxicity or thyrotoxicosis; fever may indicate encephalitis or porphyria 4
• Conduct focused neurological exam looking for focal deficits that would suggest structural brain lesion requiring urgent imaging 1, 2
• Assess level of consciousness and orientation—altered consciousness suggests delirium or medical emergency requiring different management 1, 2
• Test for asterixis and myoclonus which suggest metabolic encephalopathy rather than primary psychosis 2
• Evaluate motor behavior for catatonia, agitation, or abnormal movements 2

Laboratory Testing

Essential Initial Tests

• Complete blood count 4
• Comprehensive metabolic profile including renal and hepatic function 1, 4
• Thyroid function tests 4
• Urine toxicology screen (illicit drug use is the most common medical cause of acute psychosis) 1, 4
• Calcium and parathyroid hormone levels 4
• Vitamin B12, folate, and niacin levels 4

Additional Testing Based on Clinical Suspicion

• HIV testing and syphilis serology should be considered 4
• Toxicology screens as indicated by history and examination 1
• Baseline laboratory monitoring for potential adverse effects of antipsychotic medications 1

Neuroimaging

Indications for CT Head Without Contrast

• CT head without IV contrast is usually appropriate as first-line neuroimaging when focal neurologic deficits are present 1
• Consider neuroimaging in new-onset psychosis when the clinical picture is unclear, presentation is atypical, or there are abnormal findings on examination 1, 2
• The diagnostic yield of CT in detecting pathology responsible for psychotic symptoms is very low (0-1.5%) in patients without neurologic deficits 1
• Specific indications include: suspected stroke, focal neurologic deficit, seizure, head trauma, or headache 1

When Neuroimaging May Not Be Required

• Neuroimaging evaluation is not always required in new-onset psychosis without neurologic deficits or atypical features 1
• Individual assessment of risk factors should guide the decision for neuroimaging 1

MRI Considerations

• Brain MRI is preferred over CT when neuroimaging is indicated, as it provides more detailed information 1
• MRI without IV contrast is appropriate for known intracranial pathology or certain medical conditions associated with intracranial injury 1

Additional Diagnostic Procedures

When to Consider Further Testing

• Electroencephalography should be ordered as indicated based on history and physical examination, particularly if seizure disorder is suspected 1
• Consultation with other medical specialties may be required in some cases 1
• Consider CNS lesions, tumors, infections, metabolic disorders, and seizure disorders as potential organic causes 1

Common Pitfalls to Avoid

• Don't miss delirium: Fluctuating consciousness, disorientation, and inattention distinguish delirium from psychosis and require different urgent evaluation 2
• Don't overlook withdrawal states: Alcohol or benzodiazepine withdrawal can cause both psychosis and life-threatening seizures requiring immediate benzodiazepine treatment 2
• Don't delay neuroimaging when focal neurological signs, head trauma history, or atypical features are present 2
• Don't assume primary psychiatric disorder without ruling out medical emergencies and investigating underlying causes including CNS infections and traumatic brain injury 2

Distinguishing Primary from Secondary Psychosis

• Patients with primary psychiatric disorders typically have auditory hallucinations, prominent cognitive disorders, and complicated delusions 4
• Medical causes more commonly present with cognitive changes, abnormal vital signs, and visual hallucinations 4
• Subacute onset should raise suspicion for oncologic causes 4