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Last reviewed: 6 Nov 2023
Last updated: 26 Oct 2023



History and exam

Key diagnostic factors

  • auditory hallucinations
  • delusions
  • avolition
  • anhedonia
  • asocial behavior
  • affective blunting
  • alogia
  • cognitive deficits
  • somatization
More key diagnostic factors

Other diagnostic factors

  • lack of insight (anosognosia)
  • bizarre or disorganized behavior
  • tangentiality and looseness of association (derailment)
  • circumstantiality
  • pressured speech
  • distractible speech
  • depression
  • suicidality
  • anxiety
  • elation
  • incongruent affect
  • verbigeration
  • perseveration
  • word salad
  • derealization
  • nonauditory hallucinations
  • déjà-vu
  • stilted goal-directed behaviors
  • catatonic symptoms
  • "soft" neurologic deficits
Other diagnostic factors

Risk factors

  • family history of schizophrenia
  • increasing paternal age
  • obstetric complications
  • cannabis use
  • low IQ
  • motor dysfunction
  • psychological stress
  • childhood abuse
  • migrant status
More risk factors

Diagnostic investigations

1st investigations to order

  • clinical diagnosis
More 1st investigations to order

Investigations to consider

  • MRI/CT head
  • serum HIV enzyme-linked immunosorbent assay
  • serum rapid plasma reagin (RPR) test
  • CBC including absolute neutrophil count (ANC)
  • drug toxicology screen
  • BUN and electrolytes
  • liver function tests
  • thyroid-stimulating hormone
  • pregnancy test
  • genetic testing
More investigations to consider

Treatment algorithm


at risk of developing psychosis


acute psychotic episode


chronic symptoms

treatment-resistant schizophrenia



Xiaoduo Fan, MD, MPH, MSc

Professor of Psychiatry

Director, UMass MIND

UMass Memorial Health/UMass Chan Medical School




XF has received research support from Otsuka, Roche, and Intra-Cellular Therapies. XF has served as a reviewer for various Substance Abuse and Mental Health Services Administration (SAMHSA) federal grant programs; he has also served on the Patient Centered Outcome Research Institute (PCORI) Advisory Panel on Healthcare Delivery and Disparities Research. XF is a member of the American Psychiatric Association (APA) Scientific Program Committee, and is a member of the APA Council on International Psychiatry and Global Health.


Dr Xiaoduo Fan would like to gratefully acknowledge Dr Adrian Preda and Dr Robert G. Bota, previous contributors to this topic.


AP and RGB declare that they have no competing interests.

Peer reviewers

David Taylor, PhD

Chief Pharmacist

South London and Maudsley NHS Foundation Trust




DT declares that he has no competing interests.

Joel Yager, MD


Department of Psychiatry

University of New Mexico School of Medicine




JY declares that he has no competing interests.

Kemal Sagduyu, MD

Professor of Psychiatry

University of Missouri Kansas City

Kansas City



KS declares that he has no competing interests.

  • Differentials

    • Schizoaffective disorder
    • Schizophreniform disorder and brief psychotic disorder
    • Substance-induced psychotic disorder
    More Differentials
  • Guidelines

    • Diagnostic and statistical manual of mental disorders, fifth edition (DSM-5-TR)
    • Evidence-based guidelines for the pharmacological treatment of schizophrenia
    More Guidelines
  • Patient leaflets

    Schizophrenia: what is it?

    Schizophrenia: what treatments work?

    More Patient leaflets
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