# Evidence-based assessment/Schizophrenia (disorder portfolio)

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## What is a "portfolio"?

For background information on what assessment portfolios are, click the link in the heading above.
Want even 'more' information about this topic? There's an extended version of this page here.

## Preparation phase
### 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 schizophrenia spectrum and other psychotic disorders changed slightly from DSM-IV to DSM-5. A summary is available here.

### Base rates of schizophrenia in different populations and clinical settings

| Demography | Setting | Base Rate | Diagnostic Method |
| 48 contiguous US states | Non-institutionalized civilians | 0.5% | CIDI, SCID |
| Urban settings in 5 states (MD, NC, CN, CA, MO) | Community sample | 1.3% | DIS |
| All Federal Penitentiaries in Quebec-incarcerated and inmates currently hospitalized involuntarily | Inmates with severe mental disorders | 23.5% incarcerated†, 69.7% hospitalized involuntarily† | SCID |
| New Jersey | Patients presenting for inpatient and ambulatory services | 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”) | BASIC-32 |
| Global – 44 countries | General population (community, inpatient, and outpatient) | 0.7% | Clinical interview |
| Finland | General population | 0.87% | CIDI, SCID |
| San Diego County | County Mental Health Service Users | 54% - homeless individuals | Chart Diagnosis |
| Maryland | Inpatient service | 39% - non-homeless 8.4% - 65 years and up 17% - 19-64 years | Psychiatrist Diagnosis |
| USA (Note: Medicaid rate was calculated using California Medi-Cal rates as a proxy) | Insurance claimants in 2002 | Medicaid – 1.66%, Uninsured – 1.02%, Medicare – 0.83%, Privately insured – 0.13%, Veterans (through VA) – 1.41% | 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

## Prediction phase
### Recommended screening instruments

The following section contains a list of screening and diagnostic instruments for schizophrenia.
| Screening Instrument | Format | Age Range | Administration Time | Where to Access |
| Bonn Scale for the Assessment of Basic Symptoms (BSABS) | 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 |
Note: Reliability and validity are included in the extended version. This table includes measures with Good or Excellent ratings.

### 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) | Clinical generalizability | Where to Access |
| Psychiatric Diagnostic Screening Questionnaire – PDSQ (Zimmerman & Mattia, 2001a; Zimmerman & Sheeran, 2004)‡ | .92 (N = 799) | 2.7 (Subscale cutoff score = 1) | .33 (Subscale cutoff score = 1) | 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, 2003) | Not given (N = 34) | 3.5 (not given) | 0 (not given) | 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; Klosterkotter, Hellmich, Steinmeyer, Schultze-Lutter, 2001)• 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 (*) | Moderate - has some predictive validity for individuals who are in prodromal period of schizophrenia overall, cluster 1 has best predictive accuracy and may be most useful. | Available from Amazon Available from publisher Shaker Verlag |
| Symptom Severity Scale of the DSM5 | 0.85 (N = 314) | 3.53 | 0.35 | 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) | 0.91 (N = 314) | N/A | N/A | Note: 45 minute clinical interview. Requires training. Attached to appendix. | Not free |
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.

## Prescription phase
### Gold standard diagnostic interviews

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

### Recommended diagnostic interviews for schizophrenia

| Diagnostic Interview | Format | Age Range/ | Administration Time | Where to Access |
| Structured Clinical Interview for DSM-V (SCID) | Semi-structured interview to be administered by a clinician or an experienced rater | Adults (Ages 18+) | Varies, 43.0±30.6 minutes | -Available for purchase from APA Publishing (Note: Not free) -Modified Version (not most recent version, SCID-I) -Located on Penn Lab, See Appendix 1 for schizophrenia modules |
| Structured Interview for Psychosis-Risk Syndrome (SIPS) | 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 |
| Mini-International Neuropsychiatric Interview (MINI) | Structured interview to be administer by a mental health professional with extensive training | Adults, also a children and adolescent version available | Mean 18.7 minutes | -Available on the Harm Research Institute for purchase |
| For Children and Adolescents Specifically |||||
| 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 |
Note: Reliability and validity are included in the extended version. This table includes measures with Good or Excellent ratings.

## Process phase

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

* Information on how to interpret this table can be found here.
* For clinically significant change benchmarks for the CBCL, YSR, and TRF total, externalizing, internalizing, and attention benchmarks, see here.

#### Clinically significant change benchmarks with common instruments for schizophrenia

| Measure | Scale | Cut Scores* | Cut Scores* | Cut Scores* | Critical Change (Unstandardized Scores) | Critical Change (Unstandardized Scores) | Critical Change (Unstandardized Scores) |
| | | A | B | C | 95% | 90% | SE$_{difference}$ |
| 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 |
| Positive and Negative Syndrome Scale (1987 Norms) | PANSS Negative Scale | 8.8 | n/a | n/a | 7.0 | 5.9 | 3.6 |
| Positive and Negative Syndrome Scale (1987 Norms) | 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 |
| Scale for the Assessment of Positive Symptoms (SAPS) and Negative Symptoms (SANS) (1991 Norms) | SANS | 0.6 | n/a | n/a | 13.9 | 11.7 | 7.1 |
| 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

### Treatment

See Management of Schizophrenia.

## External Resources

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

## Web-based resources

Online Support Group for Family Members & Individuals with Schizophrenia
Website
Chatrooms for Individuals with Schizophrenia:
* http://www.schizophrenia-online.com/
* http://theircvillage.com/chat/
General Information about Schizophrenia