Psychosis, Acute



Disorder of brain function characterized illogical, bizarre, or delusional beliefs, abnormal perceptions, and disorganization of emotions, thought, and behavior


  • Primary psychotic disorders:
    • Schizophrenia: >6 mo 2 of the following: Hallucinations, delusions, negative symptoms, disorganized thought, disorganized behavior
    • Brief psychotic disorder if symptoms <1 mo, schizophreniform disorder if symptoms 1–6 mo
    • Schizoaffective disorder: Prominent mood symptoms concurrent with psychotic decompensations
    • Delusional disorder: Presence of rigid delusion without other symptoms of psychosis
  • Mood disorders:
    • Mania with psychotic features
    • Depression with psychotic features
  • Psychiatric mimics of psychosis (not true psychotic disorders but may resemble them):
    • Posttraumatic stress disorder: May involve strong referential thinking and fear of being in danger out of proportion with objective reality
    • Borderline personality disorder: May involve strong referential thinking and related affective lability
    • Obsessive-compulsive disorder: Nature of obsessions may be so illogical and rigid as to seem psychotic
    • Neurodevelopmental disorders: Those with autism or intellectual disability may have odd/bizarre/unrealistic beliefs or experience internal thoughts as “voices”

Medical, Nonpsychiatric
  • Neurologic disease:
    • Delirium (prominent confusion, inattentiveness, waxing/waning level of consciousness; may include perceptual disturbances and illogical/delusional thinking)
    • Head injury
    • Dementia (hallucinations and delusions may occur in any dementia including Alzheimer, Lewy body, frontotemporal)
    • Cerebrovascular accident (acute or chronic)
    • Seizures (inter-/postictal)
    • Space-occupying lesions (neoplasm, abscesses, cysts)
    • Hydrocephalus
    • Demyelinating diseases (multiple sclerosis)
    • Neuropsychiatric disorders (Parkinson disease, Huntington disease, Wilson disease)
    • Prion disease
  • Infectious disease:
    • Meningitis/encephalitis (bacterial, viral, or fungal)
    • HIV
    • Tertiary syphilis
    • Tertiary Lyme disease
  • Metabolic:
    • Intoxication (psychostimulants, hallucinogens, ketamine, phencyclidine, cannabinoids, MDMA, dextromethorphan)
    • Adverse medication effect (cyclosporine, cycloserine, corticosteroids, fluoroquinolones, amantadine, levodopa, pramipexole, levetiracetam)
    • Hypercalcemia
    • B12 deficiency
    • Heavy metal poisoning (arsenic, mercury)
    • Porphyria
  • Endocrine:
    • Thyroid disease
    • Cushing syndrome
    • Adrenal insufficiency
  • Autoimmune disease:
    • Lupus cerebritis (usually accompanies neurologic symptoms such as seizure)
    • Autoimmune encephalitis (i.e., anti-NMDA)
    • Paraneoplastic syndrome
  • Toxins:
    • Heavy metals
    • Organophosphates
    • Carbon monoxide

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