Evidence-based assessment/Schizophrenia (disorder portfolio)/extended version

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Diagnostic Criteria for Schizophrenia


ICD-11 Diagnostic Criteria

  • Schizophrenia
    • Schizophrenia is characterized by disturbances in multiple mental modalities, including thinking (e.g., delusions, disorganization in the form of thought), perception (e.g., hallucinations), self-experience (e.g., the experience that one's feelings, impulses, thoughts, or behaviour are under the control of an external force), cognition (e.g., impaired attention, verbal memory, and social cognition), volition (e.g., loss of motivation), affect (e.g., blunted emotional expression), and behaviour (e.g.,behaviour that appears bizarre or purposeless, unpredictable or inappropriate emotional responses that interfere with the organization of behaviour). Psychomotor disturbances, including catatonia, may be present. Persistent delusions, persistent hallucinations, thought disorder, and experiences of influence, passivity, or control are considered core symptoms. Symptoms must have persisted for at least one month in order for a diagnosis of schizophrenia to be assigned. The symptoms are not a manifestation of another health condition (e.g., a brain tumour) and are not due to the effect of a substance or medication on the central nervous system (e.g., corticosteroids), including withdrawal (e.g., alcohol withdrawal).
  • Schizophrenia, First Episode
    • Schizophrenia, first episode should be used to identify individuals experiencing symptoms that meet the diagnostic requirements for Schizophrenia (including duration) but who have never before experienced an episode during which diagnostic requirements for Schizophrenia were met.
      • Note: The ICD-11 lists 3 additional subcategories of schizophrenia, first episode. They can be found here.
  • Schizophrenia, Multiple Episodes
    • Schizophrenia, multiple episode should be used to identify individuals experiencing symptoms that meet the diagnostic requirements for Schizophrenia (including duration) and who have also previously experienced episodes during which diagnostic requirements were met, with substantial remission of symptoms between episodes. Some attenuated symptoms may remain during periods of remission, and remissions may have occurred in response to medication or other treatment.
      • Note: The ICD-11 lists 3 additional subcategories of schizophrenia, multiple episodes. They can be found here.

Changes in DSM-5 The diagnostic criteria for depressive disorders changed slightly from DSM-IV to DSM-5. A summary is available here.

Base rates of schizophrenia in different populations and clinical settings


This section describes the demographic setting of the population(s) sampled, base rates of diagnosis, country/region sampled and the diagnostic method that was used. Using this information, clinicians will be able to anchor the rate of schizophrenia they are likely to see in their clinical practice.

  • To find prevalence rates across multiple disorders, click here.
Setting Base Rate Demography Diagnostic Method Best Recommended For
Non-institutionalized civilians[1] 0.5% 48 contiguous US states CIDI, SCID
Community sample[2] 1.3% Urban settings in 5 states (MD, NC, CN, CA, MO) DIS
Inmates with severe mental disorders[3] 23.5% incarcerated†, 69.7% hospitalized involuntarily† All Federal Penitentiaries in Quebec-incarcerated and inmates currently hospitalized involuntarily SCID
Patients presenting for inpatient and ambulatory services[4]
  • African-American (males – 19.1%, females – 11.3%)
  • Latino (males – 9.4%, females – 6.2%)
  • European-American (males – 9.9%, females – 6.1%)
  • (Rates are for all psychotic disorders – authors note this was “mostly schizophrenia”)
New Jersey BASIS-32
General population (community, inpatient, and outpatient)[5] 0.7% Global – 44 countries Clinical interview
General population[6] 0.87% Finland CIDI, SCID
County Mental Health Service Users[7] 54% - homeless individuals San Diego County Chart Diagnosis
Inpatient service[8]
  • 39% - non-homeless
  • 8.4% - 65 years and up
  • 17% - 19-64 years
Maryland Psychiatrist Diagnosis
Insurance claimants in 2002[9] Medicaid – 1.66%, Uninsured – 1.02%, Medicare – 0.83%, Privately insured – 0.13%, Veterans (through VA) – 1.41% USA (Note: Medicaid rate was calculated using California Medi-Cal rates as a proxy) Physician diagnosis

†Rates reflect schizophrenia spectrum disorders. Note: DIS = Diagnostic Interview Schedule, CIDI = Composite International Diagnostic Interview, SCID = Structured Diagnostic Interview for DSM, BASIC-32 = Behavior and Symptoms Identification Scale

Search terms: [Schizophrenia] AND [prevalence OR incidence], [Schizophrenia] AND [Prevalence] AND [Outpatient OR inpatient] in PsycINFO, Medline, and PubMed

Screening instruments for schizophrenia


The following section contains a list of screening and diagnostic instruments for schizophrenia. The section includes administration information, psychometric data, and PDFs or links to the screenings. Screenings are used as part of the prediction phase of assessment; for more information on interpretation of this data, or how screenings fit in to the assessment process, click here.

Screening Instrument Format Population Administration Time Resources
Psychiatric Diagnostic Screening Questionnaire (PDSQ)[10] Self-report, yes-or-no items Ages 18+ 15-20 minutes -Available from Western Psychological Services
Structured Interview for Psychosis-Risk Syndrome (SIPS) [11] Structured interview by a clinician or experienced rater Pre-clinical adolescents and adults 2-3 hours -Available from PRIME clinic at Yale University, contact Dr. Barbara Walsh at 203-974-7052

-PDF Version

Bonn Scale for the Assessment of Basic Symptoms (BSABS)[11] Semi-structured interview by a clinician or experienced rater Pre-clinical, residual, and at-risk adolescents and adults 2-3 hours -Available from Amazon

-Available from publisher Shaker Verlag

Strengths and Difficulties Questionnaire (SDQ) [12] Parent/teacher-report, self-report, rate items Ages 2+ 5-25 minutes -Available from Youth In Mind

-PDF Version

-Strengths and Difficulties Questionnaire for parents or educators of 2-4 year olds Assessment Center Link

-Strengths and Difficulties Questionnaire for parents or teachers of 4-10 year olds Assessment Center Link

-Strengths and Difficulties Questionnaire for parents or teachers of 11-17 year olds Assessment Center Link

-Strengths and Difficulties Questionnaire (Child Self-Report) [age 11-17] Assessment Center Link

-Strengths and Difficulties Questionnaire for self-report by those aged 18+ Assessment Center Link

-Strengths and Difficulties Questionnaire for informant report on those aged 18+ Assessment Center Link

Achenbach System of Empirically Based Assessment (ASEBA) Parent/teacher/caregiver-report, self-report, rate and written items Ages 1.5+ 10-15 minutes -Available from ASEBA Store

Likelihood ratios and AUCs of screening measures for schizophrenia

  • For a list of the likelihood ratios for more broadly reaching screening instruments, click here.
Screening Measure (Primary Reference) AUC LR+ (Score) LR- (Score) Citation Clinical generalizability Download Link
Psychiatric Diagnostic Screening Questionnaire – PDSQ (Zimmerman & Mattia, 2001a)[13] .92 (N = 799) 2.7 (Subscale cutoff score = 1) .33 (Subscale cutoff score = 1) (Zimmerman & Sheeran, 2004)[14] Low – can distinguish psychotic disorders from non-psychotic disorders but cannot distinguish schizophrenia from other psychotic disorders (ex: MDD with psychosis) Not free
Structured Interview for Prodromal Syndromes – SIPS (Miller et al., 1999)[15] Not given (N = 34) 3.5 (not given) 0 (not given) (Miller et al., 2003)[16] Moderate – has some predictive validity (46% of those identified as prodromal by the SIPS developed schizophrenia psychosis within 6 mo.) SIPS
Bonn Scale for the Assessment of basic Symptoms – BSABS (Gross, 1989)[17]
  • Cluster 1 = thought, language, perception, and motor disturbances
  • Cluster 2 = impaired bodily sensations
  • Cluster 3 = impaired tolerance to normal stress
  • Cluster 4 = disorders of emotion and affect including impaired thought, energy, concentration, and memory
  • Cluster 5 = increased emotional reactivity, impaired ability to maintain or initiate social contacts, and disturbances in nonverbal expression
(N = 160)
  • C1 = 0.81
  • C2 = 0.50
  • C3 = 0.52
  • C4 = 0.57
  • C5 = 0.58
Overall = 2.4 (>=1)
  • C1 = 3.1
  • C2 = 0.48
  • C3 = 0.97
  • C4 = 1.1
  • C5 = 1.4 (*)
Overall = 0.03 (>=1)
  • C1 = 0.52
  • C2 = 1.0
  • C3 = 0.77
  • C4 = 0.5
  • C5 = 0.70 (*)
(Klosterkotter, Hellmich, Steinmeyer, Schultze-Lutter, 2001)[18] Moderate – has some predictive validity for individuals who are in the prodromal period or suspected to be in the prodromal period of schizophrenia overall, cluster 1 has best predictive accuracy and may be most useful Not found
Symptom Severity Scale of the DSM5 0.85 (N=314) 3.53 0.35 Ritsner, Mar, Arbitman, & Grinshpoon (2013) Medium: Schizophrenia versus all other psychotic disorders, but has not been studied in a variety of populations with schizophrenia as it is a relatively new measure. DSM 5 Scale
Positive and Negative Syndrome Scale (PANSS)

(Stanley, Flszbein, & Opfer, 1987)

0.91 (N=314) N/A N/A Ritsner, Mar, Arbitman, & Grinshpoon (2013) Note: 45 minute clinical interview. Requires training. Attached to appendix. Not free
NIMH: Diagnostic Interview Schedule – Psychotic Symptoms Scale

(Robins et al., 1981).

N/A 4.4 1.7 Eaton et al. (1991) Note: Quick self-report interview that screens for psychotic symptoms. Should be followed up with more indepth diagnostic assessments. Not found
Royal Park Multi- Diagnostic Instrument for Psychosis (RPMIP) (McGorry, Copolov, & Singh (1990). 0.78 (N=200) 0.8 1.625 McGorry, McKenzie, & Jackson (2000) Note: Interview that requires training. Not found
Schizotypal Personality Questionnaire (SPQ) and Survey of Attitudes and Experiences (SAE) 0.74 (N=339) 1.76 0.59 Venables & Raine (2015) Note: Samples included young, predominantly female samples of nonclinical controls.

Self-report measure, likelihood ratios are composite scores for three factors


(SAE not found)

UCSD performance-based skills assessment (UPSA) in predicting independence 0.74 (N=434) 2.03 0.47 Mausbach et al. (2008) Note: Two cut-off scores were suggested for predicting independent living in this population. These data are based on the cut-off score of 75 (greater sensitivity) Not found

Note: ‡ Used the SCID administered by trained raters. • Used Present State Examination 9 and psychiatrist diagnosis. (*) Cutoff score for all clusters was 15% of symptoms in that cluster present (for cluster 1= 5/35 symptoms)

  • “LR+” refers to the change in likelihood ratio associated with a positive test score, and “LR-” is the likelihood ratio for a low score. Likelihood ratios of 1 indicate that the test result did not change impressions at all. LRs larger than 10 or smaller than .10 are frequently clinically decisive; 5 or .20 are helpful, and between 2.0 and .5 are small enough that they rarely result in clinically meaningful changes of formulation (Sackett et al., 2000).

Search terms: [schizophrenia] AND [sensitivity OR specificity] AND [differential diagnosis] AND [prodrome] in MedLine and PsycINFO

Interpreting schizophrenia screening measure scores

  • For information on interpreting screening measure scores, click here.

Gold standard diagnostic interviews


For a list of broad reaching diagnostic interviews sortable by disorder with PDFs (if applicable), click here.

Diagnostic Interview Format Population Administration Time Resources
Structured Clinical Interview for DSM-V (SCID)[19] Semi-structured interview to be administered by a clinician or an experienced rater Adults

(Ages 18+)

Varies -Available for purchase from APA Publishing (Note: Not free)

-Modified [1] (not most recent version, SCID-I)

-Located on Penn Lab, See Appendix 1 for schizophrenia modules

Structured Clinical Interview for DSM-V Childhood Disorder (Kid SCID) Structured interview -Not found (not released)
Kiddie Schedule for Affective Disorders and Schizophrenia Present and Lifetime Version (KSADS-PL DSM-V) Semi-structured interview to be administered by a health care provider or highly trained clinical researcher Ages 6-18 45-75 minutes -PDF Version
Mini-International Neuropsychiatric Interview for Children and Adolescents (MINI Kid) Structured interview to be administer by a mental health professional with license or permission from Dr. David Sheehan Ages 6-17 40 minutes -Available from Mapi Research Trust (Note: Contact and order from Dr. David Sheehan)

The following section contains a list of process and outcome measures for schizophrenia. The section includes benchmarks based on published norms and on mood samples for several outcome and severity measures, as well as information about commonly used process measures. Process and outcome measures are used as part of the process phase of assessment. For more information of differences between process and outcome measures, see the page on the process phase of assessment.

Severity and outcome


Clinically significant change benchmarks with common instruments for schizophrenia

Measure Scale Cut Scores* Critical Change
(Unstandardized Scores)
A B C 95% 90% SEdifference
Benchmarks Based on Published Norms for Samples with Schizophrenia
Positive and Negative Syndrome Scale
(1987 Norms)
PANSS Positive Scale 6 n/a n/a 8.8 7.4 4.5
PANSS Negative Scale
8.8 n/a n/a 7.0 5.9 3.6
PANSS General Psychopathology Scale
18.8 n/a n/a 9.5 8.0 4.8
Scale for the Assessment of Positive Symptoms (SAPS) and Negative Symptoms (SANS)
(1991 Norms)
SAPS -6.9 n/a n/a 13.4 11.3 6.8
0.6 n/a n/a 13.9 11.7 7.1
Satisfaction with Life Scale (SWLS)
SWLS 5.8 36.4 22.1 7.3 6.2 3.7
Cogtest Battery Composite Score
34 70 55 9.9 8.3 5.0
Beck Depression Inventory 4 22 15 9 8 4.8
Overall Functioning: Global Assessment of Functioning (GAF) 26.8 81.6 54.8 8.3 7.0 4.2
Social Skills (Social Functioning Scale) 90.9 268.7 102.1 7.2 6.0 3.6

Note: “A” = Away from the clinical range, “B” = Back into the nonclinical range, “C” = Closer to the nonclinical than clinical mean.

Note: Clinical significance may be limited for use in schizophrenia as the disorder is currently incurable and the extent to which a return to normal functioning may be less common. For this reason, some investigators have used methods other than those proposed by Jacobson and Truax (1991) to develop cut-off points (Jacobson et al. 1999).

  • Example: Positive and Negative Syndrome Scale (PANSS) cut-off scores of 40, 45 and 50 have been mentioned for clinically significant change for schizophrenia patients in hospital settings (Schennach et al. 2015).

Search terms: [schizophrenia] AND [clinical significance OR outcomes OR change] AND [PANSS OR SWLS] in MedLine and PsycINFO



Cognitive behavioral therapy to routine care has shown limited evidence of an average effect size on psychosis symptoms. However, individual CBT is not widely available in the US, and group CBT is likely more cost-efficient. Other general treatment information can be found here.

External Resources

  1. ICD-11 diagnostic criteria
  2. Find-a-Therapist (a curated list of find-a-therapist websites where you can find a provider)
  3. NIMH (information about schizophrenia)
  4. OMIM (Online Mendelian Inheritance in Man)
    1. 181500

Web-based resources


Online Support Group for Family Members & Individuals with Schizophrenia


Chatrooms for Individuals with Schizophrenia:

General Information about Schizophrenia


Click here for references
  1. Kessler, RC; McGonagle, KA; Zhao, S; Nelson, CB; Hughes, M; Eshleman, S; Wittchen, HU; Kendler, KS (January 1994). "Lifetime and 12-month prevalence of DSM-III-R psychiatric disorders in the United States. Results from the National Comorbidity Survey.". Archives of general psychiatry 51 (1): 8-19. PMID 8279933. 
  2. Robins, Lee N., ed (1991). Psychiatric disorders in America : the epidemiologic catchment area study. New York: Free Press. ISBN 9780029265710. 
  3. Dumais, A; Côté, G; Lesage, A (March 2010). "Clinical and sociodemographic profiles of male inmates with severe mental illness: a comparison with voluntarily and involuntarily hospitalized patients.". Canadian journal of psychiatry. Revue canadienne de psychiatrie 55 (3): 172-9. PMID 20370968. 
  4. Minsky, S; Vega, W; Miskimen, T; Gara, M; Escobar, J (June 2003). "Diagnostic patterns in Latino, African American, and European American psychiatric patients.". Archives of general psychiatry 60 (6): 637-44. PMID 12796227. 
  5. Saha, Sukanta; Chant, David; Welham, Joy; McGrath, John (May 2005). "A systematic review of the prevalence of schizophrenia". PLoS medicine 2 (5): e141. doi:10.1371/journal.pmed.0020141. ISSN 1549-1676. PMID 15916472. PMC PMC1140952. https://www.ncbi.nlm.nih.gov/pubmed/15916472. 
  6. Perälä, Jonna; Suvisaari, Jaana; Saarni, Samuli I.; Kuoppasalmi, Kimmo; Isometsä, Erkki; Pirkola, Sami; Partonen, Timo; Tuulio-Henriksson, Annamari et al. (January 2007). "Lifetime prevalence of psychotic and bipolar I disorders in a general population". Archives of General Psychiatry 64 (1): 19–28. doi:10.1001/archpsyc.64.1.19. ISSN 0003-990X. PMID 17199051. https://www.ncbi.nlm.nih.gov/pubmed/17199051. 
  7. Folsom, DP; Hawthorne, W; Lindamer, L; Gilmer, T; Bailey, A; Golshan, S; Garcia, P; Unützer, J et al. (February 2005). "Prevalence and risk factors for homelessness and utilization of mental health services among 10,340 patients with serious mental illness in a large public mental health system.". The American journal of psychiatry 162 (2): 370-6. PMID 15677603. 
  8. Brown, Samuel L. (2001-06-01). "Variations in Utilization and Cost of Inpatient Psychiatric Services Among Adults in Maryland". Psychiatric Services 52 (6): 841–843. doi:10.1176/appi.ps.52.6.841. ISSN 1075-2730. https://ps.psychiatryonline.org/doi/abs/10.1176/appi.ps.52.6.841. 
  9. Wu, EQ; Shi, L; Birnbaum, H; Hudson, T; Kessler, R (November 2006). "Annual prevalence of diagnosed schizophrenia in the USA: a claims data analysis approach.". Psychological medicine 36 (11): 1535-40. PMID 16907994. 
  10. "(PDSQ™) Psychiatric Diagnostic Screening Questionnaire™ | WPS". www.wpspublish.com. Retrieved 2022-06-21.
  11. 11.0 11.1 Waters, Flavie; Stephane, Massoud. The assessment of psychosis : a reference book and rating scales for research and practice. New York, NY. ISBN 9781315885605. OCLC 897376853. https://www.worldcat.org/oclc/897376853. 
  12. Goodman, Robert; Ford, Tamsin; Simmons, Helen; Gatward, Rebecca; Meltzer, Howart (2000-12). "Using the Strengths and Difficulties Questionnaire (SDQ) to screen for child psychiatric disorders in a community sample". British Journal of Psychiatry 177 (6): 534–539. doi:10.1192/bjp.177.6.534. ISSN 0007-1250. https://www.cambridge.org/core/product/identifier/S0007125000156065/type/journal_article. 
  13. Zimmerman, M; Mattia, JI (2001). "The Psychiatric Diagnostic Screening Questionnaire: development, reliability and validity.". Comprehensive psychiatry 42 (3): 175-89. PMID 11349235. 
  14. Zimmerman, M; Sheeran, T (March 2003). "Screening for principal versus comorbid conditions in psychiatric outpatients with the Psychiatric Diagnostic Screening Questionnaire.". Psychological assessment 15 (1): 110-4. PMID 12674730. 
  15. Miller, TJ; McGlashan, TH; Woods, SW; Stein, K; Driesen, N; Corcoran, CM; Hoffman, R; Davidson, L (1999). "Symptom assessment in schizophrenic prodromal states.". The Psychiatric quarterly 70 (4): 273-87. PMID 10587984. 
  16. Miller, TJ; McGlashan, TH; Rosen, JL; Cadenhead, K; Cannon, T; Ventura, J; McFarlane, W; Perkins, DO et al. (2003). "Prodromal assessment with the structured interview for prodromal syndromes and the scale of prodromal symptoms: predictive validity, interrater reliability, and training to reliability.". Schizophrenia bulletin 29 (4): 703-15. PMID 14989408. 
  17. Gross, G (November 1989). "The 'basic' symptoms of schizophrenia.". The British journal of psychiatry. Supplement (7): 21-5; discussion 37-40. PMID 2695138. 
  18. Klosterkötter, J; Hellmich, M; Steinmeyer, EM; Schultze-Lutter, F (February 2001). "Diagnosing schizophrenia in the initial prodromal phase.". Archives of general psychiatry 58 (2): 158-64. PMID 11177117. 
  19. "Structured Clinical Interview for DSM-5 (SCID-5)". www.appi.org. Retrieved 2018-03-08.
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