← Diagnosis and Management Guides
First Episode Psychosis Workup
Key considerations: Anti-NMDA receptor encephalitis, Substance-induced psychosis, CNS infection/tumor
Cannot miss
- Anti-NMDA receptor encephalitis
- Substance-induced psychosis
- CNS infection/tumor
- Thyroid disease
- Temporal lobe epilepsy
Likely diagnoses
- Primary psychotic disorder (schizophrenia spectrum)
- Substance-induced psychosis
- Mood disorder with psychotic features
- Medical/neurological cause of psychosis
Red flags
- Age >40 at first episode (medical cause more likely)
- Rapid onset over days (vs weeks-months for primary psychiatric)
- Fever or focal neurological findings
- Visual hallucinations (auditory more typical of primary psychosis)
- Known substance use
Workup
- history: Timeline of symptom onset, substance use (including cannabis and synthetics), family psychiatric history, medical history; exam: Complete neurologic exam, mental status exam, signs of autoimmune disease, thyroid exam; labs: CBC, BMP, LFTs, TFTs, B12, folate, RPR, HIV, urine drug screen, urine pregnancy test; Anti-NMDA receptor antibodies if encephalitis suspected; imaging: Head CT then MRI brain; EEG if seizure suspected; bedside: Mental status exam, safety assessment
Management
- immediate: Treat underlying medical cause if found; Safety assessment and 1:1 observation if danger to self or others; general: If primary psychosis: low-dose antipsychotic (risperidone 1-2mg or olanzapine 5mg); Early psychosis intervention programs; Family education; Avoid high-dose antipsychotics in first episode — more sensitive to side effects
Disposition
- admit: Danger to self or others, unable to care for self, medical cause requiring workup; discharge: Stable and safe with outpatient early psychosis program and reliable follow-up; consults: Psychiatry, neurology if CNS cause suspected, rheumatology if autoimmune
Clinical pearls
- Anti-NMDA receptor encephalitis is the great mimicker — young women with new psychiatric symptoms, movement disorder, and autonomic instability need LP and antibody testing
- Complete medical workup is MANDATORY before applying a psychiatric diagnosis to first-episode psychosis
- Visual hallucinations suggest organic/medical cause; auditory hallucinations are more typical of primary psychotic disorders
Source and review
- APA Schizophrenia Treatment Guidelines 2020. Last reviewed: 2024-11-01